# Cairo Context

## class Context()

Context is the main object used when drawing with cairo. To draw with cairo, you create a Context, set the target surface, and drawing options for the Context, create shapes with functions like `Context.move_to()` and `Context.line_to()`, and then draw shapes with `Context.stroke()` or `Context.fill()`.

Contexts can be pushed to a stack via `Context.save()`. They may then safely be changed, without loosing the current state. Use `Context.restore()` to restore to the saved state.

class `cairo.``Context`(target)
  Parameters

    target – target `Surface` for the context

  Returns

    a newly allocated Context

  Raises

    `MemoryError` in case of no memory

  Creates a new Context with all graphics state parameters set to default values and with target as a target surface. The target surface should be constructed with a backend-specific function such as `ImageSurface` (or any other cairo backend surface create variant).

  `append_path`(path)
    Parameters

      path – `Path` to be appended

    Append the path onto the current path. The path may be either the return value from one of `Context.copy_path()` or `Context.copy_path_flat()` or it may be constructed manually (in C).

  `arc`(xc, yc, radius, angle1, angle2)
    Parameters

      - xc (float) – X position of the center of the arc

      - yc (float) – Y position of the center of the arc

      - radius (float) – the radius of the arc

      - angle1 (float) – the start angle, in radians

      - angle2 (float) – the end angle, in radians

    Adds a circular arc of the given radius to the current path. The arc is centered at (xc, yc), begins at angle1 and proceeds in the direction of increasing angles to end at angle2. If angle2 is less than angle1 it will be progressively increased by 2*PI until it is greater than angle1.

    If there is a current point, an initial line segment will be added to the path to connect the current point to the beginning of the arc. If this initial line is undesired, it can be avoided by calling `Context.new_sub_path()` before calling `Context.arc()`.

    Angles are measured in radians. An angle of 0.0 is in the direction of the positive X axis (in user space). An angle of PI/2.0 radians (90 degrees) is in the direction of the positive Y axis (in user space). Angles increase in the direction from the positive X axis toward the positive Y axis. So with the default transformation matrix, angles increase in a clockwise direction.

    To convert from degrees to radians, use `degrees * (math.pi / 180)`.

    This function gives the arc in the direction of increasing angles; see `Context.arc_negative()` to get the arc in the direction of decreasing angles.

    The arc is circular in user space. To achieve an elliptical arc, you can scale the current transformation matrix by different amounts in the X and Y directions. For example, to draw an ellipse in the box given by x, y, width, height:

        ctx.save()
        ctx.translate(x + width / 2., y + height / 2.)
        ctx.scale(width / 2., height / 2.)
        ctx.arc(0., 0., 1., 0., 2 * math.pi)
        ctx.restore()

  `arc_negative`(xc, yc, radius, angle1, angle2)
    Parameters

      - xc (float) – X position of the center of the arc

      - yc (float) – Y position of the center of the arc

      - radius (float) – the radius of the arc

      - angle1 (float) – the start angle, in radians

      - angle2 (float) – the end angle, in radians

    Adds a circular arc of the given radius to the current path. The arc is centered at (xc, yc), begins at angle1 and proceeds in the direction of decreasing angles to end at angle2. If angle2 is greater than angle1 it will be progressively decreased by 2*PI until it is less than angle1.

    See `Context.arc()` for more details. This function differs only in the direction of the arc between the two angles.

  `clip`()

    Establishes a new clip region by intersecting the current clip region with the current path as it would be filled by `Context.fill()` and according to the current `fill rule` (see `Context.set_fill_rule()`).

    After `clip()`, the current path will be cleared from the `Context`.

    The current clip region affects all drawing operations by effectively masking out any changes to the surface that are outside the current clip region.

    Calling `clip()` can only make the clip region smaller, never larger. But the current clip is part of the graphics state, so a temporary restriction of the clip region can be achieved by calling `clip()` within a `Context.save()`/`Context.restore()` pair. The only other means of increasing the size of the clip region is `Context.reset_clip()`.

  `clip_extents`()
    Returns

      (x1, y1, x2, y2), all float

    Return type

      tuple

    - x1: left of the resulting extents

    - y1: top of the resulting extents

    - x2: right of the resulting extents

    - y2: bottom of the resulting extents

    Computes a bounding box in user coordinates covering the area inside the current clip.

    New in version 1.4.

  `clip_preserve`()

    Establishes a new clip region by intersecting the current clip region with the current path as it would be filled by `Context.fill()` and according to the current `fill rule` (see `Context.set_fill_rule()`).

    Unlike `Context.clip()`, `clip_preserve()` preserves the path within the `Context`.

    The current clip region affects all drawing operations by effectively masking out any changes to the surface that are outside the current clip region.

    Calling `clip_preserve()` can only make the clip region smaller, never larger. But the current clip is part of the graphics state, so a temporary restriction of the clip region can be achieved by calling `clip_preserve()` within a `Context.save()`/`Context.restore()` pair. The only other means of increasing the size of the clip region is `Context.reset_clip()`.

  `close_path`()

    Adds a line segment to the path from the current point to the beginning of the current sub-path, (the most recent point passed to `Context.move_to()`), and closes this sub-path. After this call the current point will be at the joined endpoint of the sub-path.

    The behavior of `close_path()` is distinct from simply calling `Context.line_to()` with the equivalent coordinate in the case of stroking. When a closed sub-path is stroked, there are no caps on the ends of the sub-path. Instead, there is a line join connecting the final and initial segments of the sub-path.

    If there is no current point before the call to `close_path()`, this function will have no effect.

    Note: As of cairo version 1.2.4 any call to `close_path()` will place an explicit MOVE_TO element into the path immediately after the CLOSE_PATH element, (which can be seen in `Context.copy_path()` for example). This can simplify path processing in some cases as it may not be necessary to save the “last move_to point” during processing as the MOVE_TO immediately after the CLOSE_PATH will provide that point.

  `copy_clip_rectangle_list`()
    Returns

      the current clip region as a list of rectangles in user coordinates. Returns a list of `Rectangle`

    Return type

      list

    New in version 1.4.

  `copy_page`()

    Emits the current page for backends that support multiple pages, but doesn’t clear it, so, the contents of the current page will be retained for the next page too. Use `Context.show_page()` if you want to get an empty page after the emission.

    This is a convenience function that simply calls `Surface.copy_page()` on Context’s target.

  `copy_path`()
    Returns

      `Path`

    Raises

      `MemoryError` in case of no memory

    Creates a copy of the current path and returns it to the user as a `Path`.

  `copy_path_flat`()
    Returns

      `Path`

    Raises

      `MemoryError` in case of no memory

    Gets a flattened copy of the current path and returns it to the user as a `Path`.

    This function is like `Context.copy_path()` except that any curves in the path will be approximated with piecewise-linear approximations, (accurate to within the current tolerance value). That is, the result is guaranteed to not have any elements of type CAIRO_PATH_CURVE_TO which will instead be replaced by a series of CAIRO_PATH_LINE_TO elements.

  `curve_to`(x1, y1, x2, y2, x3, y3)
    Parameters

      - x1 (float) – the X coordinate of the first control point

      - y1 (float) – the Y coordinate of the first control point

      - x2 (float) – the X coordinate of the second control point

      - y2 (float) – the Y coordinate of the second control point

      - x3 (float) – the X coordinate of the end of the curve

      - y3 (float) – the Y coordinate of the end of the curve

    Adds a cubic Bézier spline to the path from the current point to position (x3, y3) in user-space coordinates, using (x1, y1) and (x2, y2) as the control points. After this call the current point will be (x3, y3).

    If there is no current point before the call to `curve_to()` this function will behave as if preceded by a call to `ctx.move_to(x1, y1)`.

  `device_to_user`(x, y)
    Parameters

      - x (float) – X value of coordinate

      - y (float) – Y value of coordinate

    Returns

      (x, y), both float

    Return type

      tuple

    Transform a coordinate from device space to user space by multiplying the given point by the inverse of the current transformation matrix (CTM).

  `device_to_user_distance`(dx, dy)
    Parameters

      - dx (float) – X component of a distance vector

      - dy (float) – Y component of a distance vector

    Returns

      (dx, dy), both float

    Return type

      tuple

    Transform a distance vector from device space to user space. This function is similar to `Context.device_to_user()` except that the translation components of the inverse CTM will be ignored when transforming (dx,dy).

  `fill`()

    A drawing operator that fills the current path according to the current `fill rule`, (each sub-path is implicitly closed before being filled). After `fill()`, the current path will be cleared from the `Context`. See `Context.set_fill_rule()` and `Context.fill_preserve()`.

  `fill_extents`()
    Returns

      (x1, y1, x2, y2), all float

    Return type

      tuple

    - x1: left of the resulting extents

    - y1: top of the resulting extents

    - x2: right of the resulting extents

    - y2: bottom of the resulting extents

    Computes a bounding box in user coordinates covering the area that would be affected, (the “inked” area), by a `Context.fill()` operation given the current path and fill parameters. If the current path is empty, returns an empty rectangle (0,0,0,0). Surface dimensions and clipping are not taken into account.

    Contrast with `Context.path_extents()`, which is similar, but returns non-zero extents for some paths with no inked area, (such as a simple line segment).

    Note that `fill_extents()` must necessarily do more work to compute the precise inked areas in light of the fill rule, so `Context.path_extents()` may be more desirable for sake of performance if the non-inked path extents are desired.

    See `Context.fill()`, `Context.set_fill_rule()` and `Context.fill_preserve()`.

  `fill_preserve`()

    A drawing operator that fills the current path according to the current `fill rule`, (each sub-path is implicitly closed before being filled). Unlike `Context.fill()`, `fill_preserve()` preserves the path within the `Context`.

    See `Context.set_fill_rule()` and `Context.fill()`.

  `font_extents`()
    Returns

      (ascent, descent, height, max_x_advance, max_y_advance), all float

    Return type

      tuple

    Gets the font extents for the currently selected font.

  `get_antialias`()
    Returns

      the current antialias mode, as set by `Context.set_antialias()`.

    Return type

      cairo.Antialias

  `get_current_point`()
    Returns

      (x, y), both float

    Return type

      tuple

    - x: X coordinate of the current point

    - y: Y coordinate of the current point

    Gets the current point of the current path, which is conceptually the final point reached by the path so far.

    The current point is returned in the user-space coordinate system. If there is no defined current point or if `Context` is in an error status, x and y will both be set to 0.0. It is possible to check this in advance with `Context.has_current_point()`.

    Most path construction functions alter the current point. See the following for details on how they affect the current point: `Context.new_path()`, `Context.new_sub_path()`, `Context.append_path()`, `Context.close_path()`, `Context.move_to()`, `Context.line_to()`, `Context.curve_to()`, `Context.rel_move_to()`, `Context.rel_line_to()`, `Context.rel_curve_to()`, `Context.arc()`, `Context.arc_negative()`, `Context.rectangle()`, `Context.text_path()`, `Context.glyph_path()`, `Context.stroke_to_path()`.

    Some functions use and alter the current point but do not otherwise change current path: `Context.show_text()`.

    Some functions unset the current path and as a result, current point: `Context.fill()`, `Context.stroke()`.

  `get_dash`()
    Returns

      (dashes, offset)

    Return type

      tuple

    - dashes: return value as a tuple for the dash array

    - offset: return value as float for the current dash offset

    Gets the current dash array.

    New in version 1.4.

  `get_dash_count`()
    Returns

      the length of the dash array, or 0 if no dash array set.

    Return type

      int

    See also `Context.set_dash()` and `Context.get_dash()`.

    New in version 1.4.

  `get_fill_rule`()
    Returns

      the current fill rule, as set by `Context.set_fill_rule()`.

    Return type

      cairo.FillRule

  `get_font_face`()
    Returns

      the current `FontFace` for the `Context`.

  `get_font_matrix`()
    Returns

      the current `Matrix` for the `Context`.

    See `Context.set_font_matrix()`.

  `get_font_options`()
    Returns

      the current `FontOptions` for the `Context`.

    Retrieves font rendering options set via `Context.set_font_options()`. Note that the returned options do not include any options derived from the underlying surface; they are literally the options passed to `Context.set_font_options()`.

  `get_group_target`()
    Returns

      the target `Surface`.

    Gets the current destination `Surface` for the `Context`. This is either the original target surface as passed to `Context` or the target surface for the current group as started by the most recent call to `Context.push_group()` or `Context.push_group_with_content()`.

    New in version 1.2.

  `get_line_cap`()
    Returns

      the current line cap style, as set by `Context.set_line_cap()`.

    Return type

      cairo.LineCap

  `get_line_join`()
    Returns

      the current line join style, as set by `Context.set_line_join()`.

    Return type

      cairo.LineJoin

  `get_line_width`()
    Returns

      the current line width

    Return type

      float

    This function returns the current line width value exactly as set by `Context.set_line_width()`. Note that the value is unchanged even if the CTM has changed between the calls to `Context.set_line_width()` and `get_line_width()`.

  `get_matrix`()
    Returns

      the current transformation `Matrix` (CTM)

  `get_miter_limit`()
    Returns

      the current miter limit, as set by `Context.set_miter_limit()`.

    Return type

      float

  `get_operator`()
    Returns

      the current compositing operator for a `Context`.

    Return type

      cairo.Operator

  `get_scaled_font`()
    Returns

      the current `ScaledFont` for a `Context`.

    New in version 1.4.

  `get_source`()
    Returns

      the current source `Pattern` for a `Context`.

  `get_target`()
    Returns

      the target `Surface` for the `Context`

  `get_tolerance`()
    Returns

      the current tolerance value, as set by `Context.set_tolerance()`

    Return type

      float

  `glyph_extents`(glyphs)
    Parameters

      glyphs – glyphs, a sequence of `Glyph`

    Return type

      TextExtents

    Gets the extents for an array of glyphs. The extents describe a user-space rectangle that encloses the “inked” portion of the glyphs, (as they would be drawn by `Context.show_glyphs()`). Additionally, the x_advance and y_advance values indicate the amount by which the current point would be advanced by `Context.show_glyphs()`.

    Note that whitespace glyphs do not contribute to the size of the rectangle (extents.width and extents.height).

  `glyph_path`(glyphs)
    Parameters

      glyphs – glyphs to show, a sequence of `Glyph`

    Adds closed paths for the glyphs to the current path. The generated path if filled, achieves an effect similar to that of `Context.show_glyphs()`.

  `has_current_point`()
    returns: True iff a current point is defined on the current path.

      See `Context.get_current_point()` for details on the current point.

    New in version 1.6.

  `identity_matrix`()

    Resets the current transformation `Matrix` (CTM) by setting it equal to the identity matrix. That is, the user-space and device-space axes will be aligned and one user-space unit will transform to one device-space unit.

  `in_fill`(x, y)
    Parameters

      - x (float) – X coordinate of the point to test

      - y (float) – Y coordinate of the point to test

    Returns

      True iff the point is inside the area that would be affected by a `Context.fill()` operation given the current path and filling parameters. Surface dimensions and clipping are not taken into account.

    See `Context.fill()`, `Context.set_fill_rule()` and `Context.fill_preserve()`.

  `in_stroke`(x, y)
    Parameters

      - x (float) – X coordinate of the point to test

      - y (float) – Y coordinate of the point to test

    Returns

      True iff the point is inside the area that would be affected by a `Context.stroke()` operation given the current path and stroking parameters. Surface dimensions and clipping are not taken into account.

    See `Context.stroke()`, `Context.set_line_width()`, `Context.set_line_join()`, `Context.set_line_cap()`, `Context.set_dash()`, and `Context.stroke_preserve()`.

  `line_to`(x, y)
    Parameters

      - x (float) – the X coordinate of the end of the new line

      - y (float) – the Y coordinate of the end of the new line

    Adds a line to the path from the current point to position (x, y) in user-space coordinates. After this call the current point will be (x, y).

    If there is no current point before the call to `line_to()` this function will behave as `ctx.move_to(x, y)`.

  `mask`(pattern)
    Parameters

      pattern – a `Pattern`

    A drawing operator that paints the current source using the alpha channel of pattern as a mask. (Opaque areas of pattern are painted with the source, transparent areas are not painted.)

  `mask_surface`(surface, x=0.0, y=0.0)
    Parameters

      - surface – a `Surface`

      - x (float) – X coordinate at which to place the origin of surface

      - y (float) – Y coordinate at which to place the origin of surface

    A drawing operator that paints the current source using the alpha channel of surface as a mask. (Opaque areas of surface are painted with the source, transparent areas are not painted.)

  `move_to`(x, y)
    Parameters

      - x (float) – the X coordinate of the new position

      - y (float) – the Y coordinate of the new position

    Begin a new sub-path. After this call the current point will be (x, y).

  `new_path`()

    Clears the current path. After this call there will be no path and no current point.

  `new_sub_path`()

    Begin a new sub-path. Note that the existing path is not affected. After this call there will be no current point.

    In many cases, this call is not needed since new sub-paths are frequently started with `Context.move_to()`.

    A call to `new_sub_path()` is particularly useful when beginning a new sub-path with one of the `Context.arc()` calls. This makes things easier as it is no longer necessary to manually compute the arc’s initial coordinates for a call to `Context.move_to()`.

    New in version 1.6.

  `paint`()

    A drawing operator that paints the current source everywhere within the current clip region.

  `paint_with_alpha`(alpha)
    Parameters

      alpha (float) – alpha value, between 0 (transparent) and 1 (opaque)

    A drawing operator that paints the current source everywhere within the current clip region using a mask of constant alpha value alpha. The effect is similar to `Context.paint()`, but the drawing is faded out using the alpha value.

  `path_extents`()
    Returns

      (x1, y1, x2, y2), all float

    Return type

      tuple

    - x1: left of the resulting extents

    - y1: top of the resulting extents

    - x2: right of the resulting extents

    - y2: bottom of the resulting extents

    Computes a bounding box in user-space coordinates covering the points on the current path. If the current path is empty, returns an empty rectangle (0, 0, 0, 0). Stroke parameters, fill rule, surface dimensions and clipping are not taken into account.

    Contrast with `Context.fill_extents()` and `Context.stroke_extents()` which return the extents of only the area that would be “inked” by the corresponding drawing operations.

    The result of `path_extents()` is defined as equivalent to the limit of `Context.stroke_extents()` with cairo.LINE_CAP_ROUND as the line width approaches 0.0, (but never reaching the empty-rectangle returned by `Context.stroke_extents()` for a line width of 0.0).

    Specifically, this means that zero-area sub-paths such as `Context.move_to()`; `Context.line_to()` segments, (even degenerate cases where the coordinates to both calls are identical), will be considered as contributing to the extents. However, a lone `Context.move_to()` will not contribute to the results of `Context.path_extents()`.

    New in version 1.6.

  `pop_group`()
    Returns

      a newly created `SurfacePattern` containing the results of all drawing operations performed to the group.

    Terminates the redirection begun by a call to `Context.push_group()` or `Context.push_group_with_content()` and returns a new pattern containing the results of all drawing operations performed to the group.

    The `pop_group()` function calls `Context.restore()`, (balancing a call to `Context.save()` by the `Context.push_group()` function), so that any changes to the graphics state will not be visible outside the group.

    New in version 1.2.

  `pop_group_to_source`()

    Terminates the redirection begun by a call to `Context.push_group()` or `Context.push_group_with_content()` and installs the resulting pattern as the source `Pattern` in the given `Context`.

    The behavior of this function is equivalent to the sequence of operations:

        group = cairo_pop_group()
        ctx.set_source(group)

    but is more convenient as their is no need for a variable to store the short-lived pointer to the pattern.

    The `Context.pop_group()` function calls `Context.restore()`, (balancing a call to `Context.save()` by the `Context.push_group()` function), so that any changes to the graphics state will not be visible outside the group.

    New in version 1.2.

  `push_group`()

    Temporarily redirects drawing to an intermediate surface known as a group. The redirection lasts until the group is completed by a call to `Context.pop_group()` or `Context.pop_group_to_source()`. These calls provide the result of any drawing to the group as a pattern, (either as an explicit object, or set as the source pattern).

    This group functionality can be convenient for performing intermediate compositing. One common use of a group is to render objects as opaque within the group, (so that they occlude each other), and then blend the result with translucence onto the destination.

    Groups can be nested arbitrarily deep by making balanced calls to `Context.push_group()`/`Context.pop_group()`. Each call pushes/pops the new target group onto/from a stack.

    The `push_group()` function calls `Context.save()` so that any changes to the graphics state will not be visible outside the group, (the pop_group functions call `Context.restore()`).

    By default the intermediate group will have a `cairo.Content` type of `cairo.Content.COLOR_ALPHA`. Other content types can be chosen for the group by using `Context.push_group_with_content()` instead.

    As an example, here is how one might fill and stroke a path with translucence, but without any portion of the fill being visible under the stroke:

        ctx.push_group()
        ctx.set_source(fill_pattern)
        ctx.fill_preserve()
        ctx.set_source(stroke_pattern)
        ctx.stroke()
        ctx.pop_group_to_source()
        ctx.paint_with_alpha(alpha)

    New in version 1.2.

  `push_group_with_content`(content)
    Parameters

      content (cairo.Content) – a content indicating the type of group that will be created

    Temporarily redirects drawing to an intermediate surface known as a group. The redirection lasts until the group is completed by a call to `Context.pop_group()` or `Context.pop_group_to_source()`. These calls provide the result of any drawing to the group as a pattern, (either as an explicit object, or set as the source pattern).

    The group will have a content type of content. The ability to control this content type is the only distinction between this function and `Context.push_group()` which you should see for a more detailed description of group rendering.

    New in version 1.2.

  `rectangle`(x, y, width, height)
    Parameters

      - x (float) – the X coordinate of the top left corner of the rectangle

      - y (float) – the Y coordinate to the top left corner of the rectangle

      - width (float) – the width of the rectangle

      - height (float) – the height of the rectangle

    Adds a closed sub-path rectangle of the given size to the current path at position (x, y) in user-space coordinates.

    This function is logically equivalent to:

        ctx.move_to(x, y)
        ctx.rel_line_to(width, 0)
        ctx.rel_line_to(0, height)
        ctx.rel_line_to(-width, 0)
        ctx.close_path()

  `rel_curve_to`(dx1, dy1, dx2, dy2, dx3, dy4)
    Parameters

      - dx1 (float) – the X offset to the first control point

      - dy1 (float) – the Y offset to the first control point

      - dx2 (float) – the X offset to the second control point

      - dy2 (float) – the Y offset to the second control point

      - dx3 (float) – the X offset to the end of the curve

      - dy3 (float) – the Y offset to the end of the curve

    Raises

      `cairo.Error` if called with no current point.

    Relative-coordinate version of `Context.curve_to()`. All offsets are relative to the current point. Adds a cubic Bézier spline to the path from the current point to a point offset from the current point by (dx3, dy3), using points offset by (dx1, dy1) and (dx2, dy2) as the control points. After this call the current point will be offset by (dx3, dy3).

    Given a current point of (x, y), `ctx.rel_curve_to(dx1, dy1, dx2, dy2, dx3, dy3)` is logically equivalent to `ctx.curve_to(x+dx1, y+dy1, x+dx2, y+dy2, x+dx3, y+dy3)`.

  `rel_line_to`(dx, dy)
    Parameters

      - dx (float) – the X offset to the end of the new line

      - dy (float) – the Y offset to the end of the new line

    Raises

      `cairo.Error` if called with no current point.

    Relative-coordinate version of `Context.line_to()`. Adds a line to the path from the current point to a point that is offset from the current point by (dx, dy) in user space. After this call the current point will be offset by (dx, dy).

    Given a current point of (x, y), `ctx.rel_line_to(dx, dy)` is logically equivalent to `ctx.line_to(x + dx, y + dy)`.

  `rel_move_to`(dx, dy)
    Parameters

      - dx (float) – the X offset

      - dy (float) – the Y offset

    Raises

      `cairo.Error` if called with no current point.

    Begin a new sub-path. After this call the current point will offset by (dx, dy).

    Given a current point of (x, y), `ctx.rel_move_to(dx, dy)` is logically equivalent to `ctx.(x + dx, y + dy)`.

  `reset_clip`()

    Reset the current clip region to its original, unrestricted state. That is, set the clip region to an infinitely large shape containing the target surface. Equivalently, if infinity is too hard to grasp, one can imagine the clip region being reset to the exact bounds of the target surface.

    Note that code meant to be reusable should not call `reset_clip()` as it will cause results unexpected by higher-level code which calls `clip()`. Consider using `save()` and `restore()` around `clip()` as a more robust means of temporarily restricting the clip region.

  `restore`()

    Restores `Context` to the state saved by a preceding call to `save()` and removes that state from the stack of saved states.

  `rotate`(angle)
    Parameters

      angle (float) – angle (in radians) by which the user-space axes will be rotated

    Modifies the current transformation matrix (CTM) by rotating the user-space axes by angle radians. The rotation of the axes takes places after any existing transformation of user space. The rotation direction for positive angles is from the positive X axis toward the positive Y axis.

  `save`()

    Makes a copy of the current state of `Context` and saves it on an internal stack of saved states. When `restore()` is called, `Context` will be restored to the saved state. Multiple calls to `save()` and `restore()` can be nested; each call to `restore()` restores the state from the matching paired `save()`.

  `scale`(sx, sy)
    Parameters

      - sx (float) – scale factor for the X dimension

      - sy (float) – scale factor for the Y dimension

    Modifies the current transformation matrix (CTM) by scaling the X and Y user-space axes by sx and sy respectively. The scaling of the axes takes place after any existing transformation of user space.

  `select_font_face`(family[, slant[, weight]])
    Parameters

      - family (text) – a font family name

      - slant (cairo.FontSlant) – the font slant of the font, defaults to `cairo.FontSlant.NORMAL`.

      - weight (cairo.FontWeight) – the font weight of the font, defaults to `cairo.FontWeight.NORMAL`.

    Note: The `select_font_face()` function call is part of what the cairo designers call the “toy” text API. It is convenient for short demos and simple programs, but it is not expected to be adequate for serious text-using applications.

    Selects a family and style of font from a simplified description as a family name, slant and weight. Cairo provides no operation to list available family names on the system (this is a “toy”, remember), but the standard CSS2 generic family names, (“serif”, “sans-serif”, “cursive”, “fantasy”, “monospace”), are likely to work as expected.

    For “real” font selection, see the font-backend-specific font_face_create functions for the font backend you are using. (For example, if you are using the freetype-based cairo-ft font backend, see cairo_ft_font_face_create_for_ft_face() or cairo_ft_font_face_create_for_pattern().) The resulting font face could then be used with cairo_scaled_font_create() and cairo_set_scaled_font().

    Similarly, when using the “real” font support, you can call directly into the underlying font system, (such as fontconfig or freetype), for operations such as listing available fonts, etc.

    It is expected that most applications will need to use a more comprehensive font handling and text layout library, (for example, pango), in conjunction with cairo.

    If text is drawn without a call to `select_font_face()`, (nor `set_font_face()` nor `set_scaled_font()`), the default family is platform-specific, but is essentially “sans-serif”. Default slant is `cairo.FontSlant.NORMAL`, and default weight is `cairo.FontWeight.NORMAL`.

    This function is equivalent to a call to `ToyFontFace` followed by `set_font_face()`.

  `set_antialias`(antialias)
    Parameters

      antialias (cairo.Antialias) – the new antialias mode

    Set the antialiasing mode of the rasterizer used for drawing shapes. This value is a hint, and a particular backend may or may not support a particular value. At the current time, no backend supports `cairo.Antialias.SUBPIXEL` when drawing shapes.

    Note that this option does not affect text rendering, instead see `FontOptions.set_antialias()`.

  `set_dash`(dashes[, offset=0])
    Parameters

      - dashes – a sequence specifying alternate lengths of on and off stroke portions as float.

      - offset (int) – an offset into the dash pattern at which the stroke should start, defaults to 0.

    Raises

      `cairo.Error` if any value in dashes is negative, or if all values are 0.

    Sets the dash pattern to be used by `stroke()`. A dash pattern is specified by dashes - a sequence of positive values. Each value provides the length of alternate “on” and “off” portions of the stroke. The offset specifies an offset into the pattern at which the stroke begins.

    Each “on” segment will have caps applied as if the segment were a separate sub-path. In particular, it is valid to use an “on” length of 0.0 with `cairo.LineCap.ROUND` or `cairo.LineCap.SQUARE` in order to distributed dots or squares along a path.

    Note: The length values are in user-space units as evaluated at the time of stroking. This is not necessarily the same as the user space at the time of `set_dash()`.

    If the number of dashes is 0 dashing is disabled.

    If the number of dashes is 1 a symmetric pattern is assumed with alternating on and off portions of the size specified by the single value in dashes.

  `set_fill_rule`(fill_rule)
    Parameters

      fill_rule (cairo.FillRule) – a fill rule to set the within the cairo context. The fill rule is used to determine which regions are inside or outside a complex (potentially self-intersecting) path. The current fill rule affects both `fill()` and `clip()`.

    The default fill rule is `cairo.FillRule.WINDING`.

  `set_font_face`(font_face)
    Parameters

      font_face – a `FontFace`, or None to restore to the default `FontFace`

    Replaces the current `FontFace` object in the `Context` with font_face.

  `set_font_matrix`(matrix)
    Parameters

      matrix – a `Matrix` describing a transform to be applied to the current font.

    Sets the current font matrix to matrix. The font matrix gives a transformation from the design space of the font (in this space, the em-square is 1 unit by 1 unit) to user space. Normally, a simple scale is used (see `set_font_size()`), but a more complex font matrix can be used to shear the font or stretch it unequally along the two axes

  `set_font_options`(options)
    Parameters

      options – `FontOptions` to use

    Sets a set of custom font rendering options for the `Context`. Rendering options are derived by merging these options with the options derived from underlying surface; if the value in options has a default value (like `cairo.Antialias.DEFAULT`), then the value from the surface is used.

  `set_font_size`(size)
    Parameters

      size (float) – the new font size, in user space units

    Sets the current font matrix to a scale by a factor of size, replacing any font matrix previously set with `set_font_size()` or `set_font_matrix()`. This results in a font size of size user space units. (More precisely, this matrix will result in the font’s em-square being a size by size square in user space.)

    If text is drawn without a call to `set_font_size()`, (nor `set_font_matrix()` nor `set_scaled_font()`), the default font size is 10.0.

  `set_line_cap`(line_cap)
    Parameters

      line_cap (cairo.LineCap) – a line cap style

    Sets the current line cap style within the `Context`.

    As with the other stroke parameters, the current line cap style is examined by `stroke()`, `stroke_extents()`, and `stroke_to_path()`, but does not have any effect during path construction.

    The default line cap style is `cairo.LineCap.BUTT`.

  `set_line_join`(line_join)
    Parameters

      line_join (cairo.LineJoin) – a line join style

    Sets the current line join style within the `Context`.

    As with the other stroke parameters, the current line join style is examined by `stroke()`, `stroke_extents()`, and `stroke_to_path()`, but does not have any effect during path construction.

    The default line join style is `cairo.LineJoin.MITER`.

  `set_line_width`(width)
    Parameters

      width (float) – a line width

    Sets the current line width within the `Context`. The line width value specifies the diameter of a pen that is circular in user space, (though device-space pen may be an ellipse in general due to scaling/shear/rotation of the CTM).

    Note: When the description above refers to user space and CTM it refers to the user space and CTM in effect at the time of the stroking operation, not the user space and CTM in effect at the time of the call to `set_line_width()`. The simplest usage makes both of these spaces identical. That is, if there is no change to the CTM between a call to `set_line_width()` and the stroking operation, then one can just pass user-space values to `set_line_width()` and ignore this note.

    As with the other stroke parameters, the current line width is examined by `stroke()`, `stroke_extents()`, and `stroke_to_path()`, but does not have any effect during path construction.

    The default line width value is 2.0.

  `set_matrix`(matrix)
    Parameters

      matrix – a transformation `Matrix` from user space to device space.

    Modifies the current transformation matrix (CTM) by setting it equal to matrix.

  `set_miter_limit`(limit)
    Parameters

      limit – miter limit to set

    Sets the current miter limit within the `Context`.

    If the current line join style is set to `cairo.LineJoin.MITER` (see `set_line_join()`), the miter limit is used to determine whether the lines should be joined with a bevel instead of a miter. Cairo divides the length of the miter by the line width. If the result is greater than the miter limit, the style is converted to a bevel.

    As with the other stroke parameters, the current line miter limit is examined by `stroke()`, `stroke_extents()`, and `stroke_to_path()`, but does not have any effect during path construction.

    The default miter limit value is 10.0, which will convert joins with interior angles less than 11 degrees to bevels instead of miters. For reference, a miter limit of 2.0 makes the miter cutoff at 60 degrees, and a miter limit of 1.414 makes the cutoff at 90 degrees.

    A miter limit for a desired angle can be computed as:

        miter limit = 1/math.sin(angle/2)

  `set_operator`(op)
    Parameters

      op (cairo.Operator) – the compositing operator to set for use in all drawing operations.

    The default operator is `cairo.Operator.OVER`.

  `set_scaled_font`(scaled_font)
    Parameters

      scaled_font – a `ScaledFont`

    Replaces the current font face, font matrix, and font options in the `Context` with those of the `ScaledFont`. Except for some translation, the current CTM of the `Context` should be the same as that of the `ScaledFont`, which can be accessed using `ScaledFont.get_ctm()`.

    New in version 1.2.

  `set_source`(source)
    Parameters

      source – a `Pattern` to be used as the source for subsequent drawing operations.

    Sets the source pattern within `Context` to source. This pattern will then be used for any subsequent drawing operation until a new source pattern is set.

    Note: The pattern’s transformation matrix will be locked to the user space in effect at the time of `set_source()`. This means that further modifications of the current transformation matrix will not affect the source pattern. See `Pattern.set_matrix()`.

    The default source pattern is a solid pattern that is opaque black, (that is, it is equivalent to `set_source_rgb(0.0, 0.0, 0.0)`.

  `set_source_rgb`(red, green, blue)
    Parameters

      - red (float) – red component of color

      - green (float) – green component of color

      - blue (float) – blue component of color

    Sets the source pattern within `Context` to an opaque color. This opaque color will then be used for any subsequent drawing operation until a new source pattern is set.

    The color components are floating point numbers in the range 0 to 1. If the values passed in are outside that range, they will be clamped.

    The default source pattern is opaque black, (that is, it is equivalent to `set_source_rgb(0.0, 0.0, 0.0)`.

  `set_source_rgba`(red, green, blue[, alpha=1.0])
    Parameters

      - red (float) – red component of color

      - green (float) – green component of color

      - blue (float) – blue component of color

      - alpha (float) – alpha component of color

    Sets the source pattern within `Context` to a translucent color. This color will then be used for any subsequent drawing operation until a new source pattern is set.

    The color and alpha components are floating point numbers in the range 0 to 1. If the values passed in are outside that range, they will be clamped.

    The default source pattern is opaque black, (that is, it is equivalent to `set_source_rgba(0.0, 0.0, 0.0, 1.0)`.

  `set_source_surface`(surface[, x=0.0[, y=0.0]])
    Parameters

      - surface – a `Surface` to be used to set the source pattern

      - x (float) – User-space X coordinate for surface origin

      - y (float) – User-space Y coordinate for surface origin

    This is a convenience function for creating a pattern from a `Surface` and setting it as the source in `Context` with `set_source()`.

    The x and y parameters give the user-space coordinate at which the surface origin should appear. (The surface origin is its upper-left corner before any transformation has been applied.) The x and y patterns are negated and then set as translation values in the pattern matrix.

    Other than the initial translation pattern matrix, as described above, all other pattern attributes, (such as its extend mode), are set to the default values as in `SurfacePattern`. The resulting pattern can be queried with `get_source()` so that these attributes can be modified if desired, (eg. to create a repeating pattern with `Pattern.set_extend()`).

  `set_tolerance`(tolerance)
    Parameters

      tolerance (float) – the tolerance, in device units (typically pixels)

    Sets the tolerance used when converting paths into trapezoids. Curved segments of the path will be subdivided until the maximum deviation between the original path and the polygonal approximation is less than tolerance. The default value is 0.1. A larger value will give better performance, a smaller value, better appearance. (Reducing the value from the default value of 0.1 is unlikely to improve appearance significantly.) The accuracy of paths within Cairo is limited by the precision of its internal arithmetic, and the prescribed tolerance is restricted to the smallest representable internal value.

  `show_glyphs`(glyphs)
    Parameters

      glyphs – glyphs to show as a sequence of `Glyph`

    A drawing operator that generates the shape from an array of glyphs, rendered according to the current font face, font size (font matrix), and font options.

  `show_page`()

    Emits and clears the current page for backends that support multiple pages. Use `copy_page()` if you don’t want to clear the page.

    This is a convenience function that simply calls `ctx.get_target() . show_page()`

  `show_text`(text)
    Parameters

      text (text) – text

    A drawing operator that generates the shape from a string of text, rendered according to the current font_face, font_size (font_matrix), and font_options.

    This function first computes a set of glyphs for the string of text. The first glyph is placed so that its origin is at the current point. The origin of each subsequent glyph is offset from that of the previous glyph by the advance values of the previous glyph.

    After this call the current point is moved to the origin of where the next glyph would be placed in this same progression. That is, the current point will be at the origin of the final glyph offset by its advance values. This allows for easy display of a single logical string with multiple calls to `show_text()`.

    Note: The `show_text()` function call is part of what the cairo designers call the “toy” text API. It is convenient for short demos and simple programs, but it is not expected to be adequate for serious text-using applications. See `show_glyphs()` for the “real” text display API in cairo.

  `stroke`()

    A drawing operator that strokes the current path according to the current line width, line join, line cap, and dash settings. After `stroke()`, the current path will be cleared from the cairo context. See `set_line_width()`, `set_line_join()`, `set_line_cap()`, `set_dash()`, and `stroke_preserve()`.

    Note: Degenerate segments and sub-paths are treated specially and provide a useful result. These can result in two different situations:

    1. Zero-length “on” segments set in `set_dash()`. If the cap style is `cairo.LineCap.ROUND` or `cairo.LineCap.SQUARE` then these segments will be drawn as circular dots or squares respectively. In the case of `cairo.LineCap.SQUARE`, the orientation of the squares is determined by the direction of the underlying path.

    2. A sub-path created by `move_to()` followed by either a `close_path()` or one or more calls to `line_to()` to the same coordinate as the `move_to()`. If the cap style is `cairo.LineCap.ROUND` then these sub-paths will be drawn as circular dots. Note that in the case of `cairo.LineCap.SQUARE` a degenerate sub-path will not be drawn at all, (since the correct orientation is indeterminate).

    In no case will a cap style of `cairo.LineCap.BUTT` cause anything to be drawn in the case of either degenerate segments or sub-paths.

  `stroke_extents`()
    Returns

      (x1, y1, x2, y2), all float

    Return type

      tuple

    - x1: left of the resulting extents

    - y1: top of the resulting extents

    - x2: right of the resulting extents

    - y2: bottom of the resulting extents

    Computes a bounding box in user coordinates covering the area that would be affected, (the “inked” area), by a `stroke()` operation given the current path and stroke parameters. If the current path is empty, returns an empty rectangle (0, 0, 0, 0). Surface dimensions and clipping are not taken into account.

    Note that if the line width is set to exactly zero, then `stroke_extents()` will return an empty rectangle. Contrast with `path_extents()` which can be used to compute the non-empty bounds as the line width approaches zero.

    Note that `stroke_extents()` must necessarily do more work to compute the precise inked areas in light of the stroke parameters, so `path_extents()` may be more desirable for sake of performance if non-inked path extents are desired.

    See `stroke()`, `set_line_width()`, `set_line_join()`, `set_line_cap()`, `set_dash()`, and `stroke_preserve()`.

  `stroke_preserve`()

    A drawing operator that strokes the current path according to the current line width, line join, line cap, and dash settings. Unlike `stroke()`, `stroke_preserve()` preserves the path within the cairo context.

    See `set_line_width()`, `set_line_join()`, `set_line_cap()`, `set_dash()`, and `stroke_preserve()`.

  `text_extents`(text)
    Parameters

      text (text) – text to get extents for

    Return type

      TextExtents

    Gets the extents for a string of text. The extents describe a user-space rectangle that encloses the “inked” portion of the text, (as it would be drawn by `Context.show_text()`). Additionally, the x_advance and y_advance values indicate the amount by which the current point would be advanced by `Context.show_text()`.

    Note that whitespace characters do not directly contribute to the size of the rectangle (extents.width and extents.height). They do contribute indirectly by changing the position of non-whitespace characters. In particular, trailing whitespace characters are likely to not affect the size of the rectangle, though they will affect the x_advance and y_advance values.

  `text_path`(text)
    Parameters

      text (text) – text

    Adds closed paths for text to the current path. The generated path if filled, achieves an effect similar to that of `Context.show_text()`.

    Text conversion and positioning is done similar to `Context.show_text()`.

    Like `Context.show_text()`, After this call the current point is moved to the origin of where the next glyph would be placed in this same progression. That is, the current point will be at the origin of the final glyph offset by its advance values. This allows for chaining multiple calls to to `Context.text_path()` without having to set current point in between.

    Note: The `text_path()` function call is part of what the cairo designers call the “toy” text API. It is convenient for short demos and simple programs, but it is not expected to be adequate for serious text-using applications. See `Context.glyph_path()` for the “real” text path API in cairo.

  `transform`(matrix)
    Parameters

      matrix – a transformation `Matrix` to be applied to the user-space axes

    Modifies the current transformation matrix (CTM) by applying matrix as an additional transformation. The new transformation of user space takes place after any existing transformation.

  `translate`(tx, ty)
    Parameters

      - tx (float) – amount to translate in the X direction

      - ty (float) – amount to translate in the Y direction

    Modifies the current transformation matrix (CTM) by translating the user-space origin by (tx, ty). This offset is interpreted as a user-space coordinate according to the CTM in place before the new call to `translate()`. In other words, the translation of the user-space origin takes place after any existing transformation.

  `user_to_device`(x, y)
    Parameters

      - x (float) – X value of coordinate

      - y (float) – Y value of coordinate

    Returns

      (x, y), both float

    Return type

      tuple

    - x: X value of coordinate

    - y: Y value of coordinate

    Transform a coordinate from user space to device space by multiplying the given point by the current transformation matrix (CTM).

  `user_to_device_distance`(dx, dy)
    Parameters

      - dx (float) – X value of a distance vector

      - dy (float) – Y value of a distance vector

    Returns

      (dx, dy), both float

    Return type

      tuple

    - dx: X value of a distance vector

    - dy: Y value of a distance vector

    Transform a distance vector from user space to device space. This function is similar to `Context.user_to_device()` except that the translation components of the CTM will be ignored when transforming (dx,dy).

  `in_clip`(x, y)

    > param float x

    >   X coordinate of the point to test

    > param float y

    >   Y coordinate of the point to test

    > returns

    >   `True` if the point is inside, or `False` if outside.

    > rtype

    >   bool

    > Tests whether the given point is inside the area that would be visible through the current clip, i.e. the area that would be filled by a `paint()` operation.

    > See `clip()`, and `clip_preserve()`.

    > New in version 1.12.0.

    `show_text_glyphs`(utf8, glyphs, clusters, cluster_flags)
      Parameters

        - utf8 (text) – a string of text

        - glyphs (list) – list of glyphs to show

        - clusters (list) – list of cluster mapping information

        - cluster_flags (TextClusterFlags) – cluster mapping flags

      Raises

        Error –

      New in version 1.15.

      This operation has rendering effects similar to `Context.show_glyphs()` but, if the target surface supports it, uses the provided text and cluster mapping to embed the text for the glyphs shown in the output. If the target does not support the extended attributes, this function acts like the basic `Context.show_glyphs()` as if it had been passed `glyphs` .

      The mapping between utf8 and glyphs is provided by a list of clusters. Each cluster covers a number of text bytes and glyphs, and neighboring clusters cover neighboring areas of utf8 and glyphs . The clusters should collectively cover utf8 and glyphs in entirety.

      The first cluster always covers bytes from the beginning of utf8 . If `cluster_flags` do not have the `TextClusterFlags.BACKWARD` set, the first cluster also covers the beginning of glyphs , otherwise it covers the end of the glyphs array and following clusters move backward.

      See `TextCluster` for constraints on valid clusters.

    `stroke_to_path`()

      Note

      This function is not implemented in cairo, but still mentioned in the documentation.