Pango.Renderer¶

class — extends GObject.Object

PangoRenderer is a base class for objects that can render text provided as PangoGlyphString or PangoLayout.

By subclassing PangoRenderer and overriding operations such as draw_glyphs and draw_rectangle, renderers for particular font backends and destinations can be created.

Methods¶

activate¶

def activate(self) -> None

Does initial setup before rendering operations on renderer.

Renderer.deactivate should be called when done drawing. Calls such as Renderer.draw_layout automatically activate the layout before drawing on it.

Calls to Renderer.activate and Renderer.deactivate can be nested and the renderer will only be initialized and deinitialized once.

deactivate¶

def deactivate(self) -> None

Cleans up after rendering operations on renderer.

See docs for Renderer.activate.

draw_error_underline¶

def draw_error_underline(self, x: int, y: int, width: int, height: int) -> None

Draw a squiggly line that approximately covers the given rectangle in the style of an underline used to indicate a spelling error.

The width of the underline is rounded to an integer number of up/down segments and the resulting rectangle is centered in the original rectangle.

This should be called while renderer is already active. Use Renderer.activate to activate a renderer.

Parameters:

x — X coordinate of underline, in Pango units in user coordinate system
y — Y coordinate of underline, in Pango units in user coordinate system
width — width of underline, in Pango units in user coordinate system
height — height of underline, in Pango units in user coordinate system

draw_glyph¶

def draw_glyph(self, font: Font, glyph: Glyph, x: float, y: float) -> None

Draws a single glyph with coordinates in device space.

Parameters:

font — a PangoFont
glyph — the glyph index of a single glyph
x — X coordinate of left edge of baseline of glyph
y — Y coordinate of left edge of baseline of glyph

draw_glyph_item¶

def draw_glyph_item(self, text: str | None, glyph_item: GlyphItem, x: int, y: int) -> None

Draws the glyphs in glyph_item with the specified PangoRenderer, embedding the text associated with the glyphs in the output if the output format supports it.

This is useful for rendering text in PDF.

Note that this method does not handle attributes in glyph_item. If you want colors, shapes and lines handled automatically according to those attributes, you need to use Renderer.draw_layout_line or Renderer.draw_layout.

Note that text is the start of the text for layout, which is then indexed by glyph_item->item->offset.

If text is None, this simply calls Renderer.draw_glyphs.

The default implementation of this method simply falls back to Renderer.draw_glyphs.

Parameters:

text — the UTF-8 text that glyph_item refers to
glyph_item — a PangoGlyphItem
x — X position of left edge of baseline, in user space coordinates in Pango units
y — Y position of left edge of baseline, in user space coordinates in Pango units

draw_glyphs¶

def draw_glyphs(self, font: Font, glyphs: GlyphString, x: int, y: int) -> None

Draws the glyphs in glyphs with the specified PangoRenderer.

Parameters:

font — a PangoFont
glyphs — a PangoGlyphString
x — X position of left edge of baseline, in user space coordinates in Pango units.
y — Y position of left edge of baseline, in user space coordinates in Pango units.

draw_layout¶

def draw_layout(self, layout: Layout, x: int, y: int) -> None

Draws layout with the specified PangoRenderer.

This is equivalent to drawing the lines of the layout, at their respective positions relative to x, y.

Parameters:

layout — a PangoLayout
x — X position of left edge of baseline, in user space coordinates in Pango units.
y — Y position of left edge of baseline, in user space coordinates in Pango units.

draw_layout_line¶

def draw_layout_line(self, line: LayoutLine, x: int, y: int) -> None

Draws line with the specified PangoRenderer.

This draws the glyph items that make up the line, as well as shapes, backgrounds and lines that are specified by the attributes of those items.

Parameters:

line — a PangoLayoutLine
x — X position of left edge of baseline, in user space coordinates in Pango units.
y — Y position of left edge of baseline, in user space coordinates in Pango units.

draw_rectangle¶

def draw_rectangle(self, part: RenderPart | int, x: int, y: int, width: int, height: int) -> None

Draws an axis-aligned rectangle in user space coordinates with the specified PangoRenderer.

This should be called while renderer is already active. Use Renderer.activate to activate a renderer.

Parameters:

part — type of object this rectangle is part of
x — X position at which to draw rectangle, in user space coordinates in Pango units
y — Y position at which to draw rectangle, in user space coordinates in Pango units
width — width of rectangle in Pango units
height — height of rectangle in Pango units

draw_trapezoid¶

def draw_trapezoid(self, part: RenderPart | int, y1_: float, x11: float, x21: float, y2: float, x12: float, x22: float) -> None

Draws a trapezoid with the parallel sides aligned with the X axis using the given PangoRenderer; coordinates are in device space.

Parameters:

part — type of object this trapezoid is part of
y1_ — Y coordinate of top of trapezoid
x11 — X coordinate of left end of top of trapezoid
x21 — X coordinate of right end of top of trapezoid
y2 — Y coordinate of bottom of trapezoid
x12 — X coordinate of left end of bottom of trapezoid
x22 — X coordinate of right end of bottom of trapezoid

get_alpha¶

def get_alpha(self, part: RenderPart | int) -> int

Gets the current alpha for the specified part.

Parameters:

part — the part to get the alpha for

get_color¶

def get_color(self, part: RenderPart | int) -> Color | None

Gets the current rendering color for the specified part.

Parameters:

part — the part to get the color for

get_layout¶

def get_layout(self) -> Layout | None

Gets the layout currently being rendered using renderer.

Calling this function only makes sense from inside a subclass's methods, like in its draw_shape vfunc, for example.

The returned layout should not be modified while still being rendered.

get_layout_line¶

def get_layout_line(self) -> LayoutLine | None

Gets the layout line currently being rendered using renderer.

Calling this function only makes sense from inside a subclass's methods, like in its draw_shape vfunc, for example.

The returned layout line should not be modified while still being rendered.

get_matrix¶

def get_matrix(self) -> Matrix | None

Gets the transformation matrix that will be applied when rendering.

See Renderer.set_matrix.

part_changed¶

def part_changed(self, part: RenderPart | int) -> None

Informs Pango that the way that the rendering is done for part has changed.

This should be called if the rendering changes in a way that would prevent multiple pieces being joined together into one drawing call. For instance, if a subclass of PangoRenderer was to add a stipple option for drawing underlines, it needs to call

pango_renderer_part_changed (render, PANGO_RENDER_PART_UNDERLINE);

When the stipple changes or underlines with different stipples might be joined together. Pango automatically calls this for changes to colors. (See Renderer.set_color)

Parameters:

part — the part for which rendering has changed.

set_alpha¶

def set_alpha(self, part: RenderPart | int, alpha: int) -> None

Sets the alpha for part of the rendering.

Note that the alpha may only be used if a color is specified for part as well.

Parameters:

part — the part to set the alpha for
alpha — an alpha value between 1 and 65536, or 0 to unset the alpha

set_color¶

def set_color(self, part: RenderPart | int, color: Color | None = ...) -> None

Sets the color for part of the rendering.

Also see Renderer.set_alpha.

Parameters:

part — the part to change the color of
color — the new color or None to unset the current color

set_matrix¶

def set_matrix(self, matrix: Matrix | None = ...) -> None

Sets the transformation matrix that will be applied when rendering.

Parameters:

matrix — a PangoMatrix, or None to unset any existing matrix (No matrix set is the same as setting the identity matrix.)

Virtual methods¶

do_begin¶

def do_begin(self) -> None

Do renderer-specific initialization before drawing

do_draw_error_underline¶

def do_draw_error_underline(self, x: int, y: int, width: int, height: int) -> None

Draw a squiggly line that approximately covers the given rectangle in the style of an underline used to indicate a spelling error.

The width of the underline is rounded to an integer number of up/down segments and the resulting rectangle is centered in the original rectangle.

This should be called while renderer is already active. Use Renderer.activate to activate a renderer.

Parameters:

x — X coordinate of underline, in Pango units in user coordinate system
y — Y coordinate of underline, in Pango units in user coordinate system
width — width of underline, in Pango units in user coordinate system
height — height of underline, in Pango units in user coordinate system

do_draw_glyph¶

def do_draw_glyph(self, font: Font, glyph: Glyph, x: float, y: float) -> None

Draws a single glyph with coordinates in device space.

Parameters:

font — a PangoFont
glyph — the glyph index of a single glyph
x — X coordinate of left edge of baseline of glyph
y — Y coordinate of left edge of baseline of glyph

do_draw_glyph_item¶

def do_draw_glyph_item(self, text: str | None, glyph_item: GlyphItem, x: int, y: int) -> None

Draws the glyphs in glyph_item with the specified PangoRenderer, embedding the text associated with the glyphs in the output if the output format supports it.

This is useful for rendering text in PDF.

Note that this method does not handle attributes in glyph_item. If you want colors, shapes and lines handled automatically according to those attributes, you need to use Renderer.draw_layout_line or Renderer.draw_layout.

Note that text is the start of the text for layout, which is then indexed by glyph_item->item->offset.

If text is None, this simply calls Renderer.draw_glyphs.

The default implementation of this method simply falls back to Renderer.draw_glyphs.

Parameters:

text — the UTF-8 text that glyph_item refers to
glyph_item — a PangoGlyphItem
x — X position of left edge of baseline, in user space coordinates in Pango units
y — Y position of left edge of baseline, in user space coordinates in Pango units

do_draw_glyphs¶

def do_draw_glyphs(self, font: Font, glyphs: GlyphString, x: int, y: int) -> None

Draws the glyphs in glyphs with the specified PangoRenderer.

Parameters:

font — a PangoFont
glyphs — a PangoGlyphString
x — X position of left edge of baseline, in user space coordinates in Pango units.
y — Y position of left edge of baseline, in user space coordinates in Pango units.

do_draw_rectangle¶

def do_draw_rectangle(self, part: RenderPart | int, x: int, y: int, width: int, height: int) -> None

Draws an axis-aligned rectangle in user space coordinates with the specified PangoRenderer.

This should be called while renderer is already active. Use Renderer.activate to activate a renderer.

Parameters:

part — type of object this rectangle is part of
x — X position at which to draw rectangle, in user space coordinates in Pango units
y — Y position at which to draw rectangle, in user space coordinates in Pango units
width — width of rectangle in Pango units
height — height of rectangle in Pango units

do_draw_shape¶

def do_draw_shape(self, attr: AttrShape, x: int, y: int) -> None

draw content for a glyph shaped with PangoAttrShape x, y are the coordinates of the left edge of the baseline, in user coordinates.

do_draw_trapezoid¶

def do_draw_trapezoid(self, part: RenderPart | int, y1_: float, x11: float, x21: float, y2: float, x12: float, x22: float) -> None

Draws a trapezoid with the parallel sides aligned with the X axis using the given PangoRenderer; coordinates are in device space.

Parameters:

part — type of object this trapezoid is part of
y1_ — Y coordinate of top of trapezoid
x11 — X coordinate of left end of top of trapezoid
x21 — X coordinate of right end of top of trapezoid
y2 — Y coordinate of bottom of trapezoid
x12 — X coordinate of left end of bottom of trapezoid
x22 — X coordinate of right end of bottom of trapezoid

do_end¶

def do_end(self) -> None

Do renderer-specific cleanup after drawing

do_part_changed¶

def do_part_changed(self, part: RenderPart | int) -> None

Informs Pango that the way that the rendering is done for part has changed.

This should be called if the rendering changes in a way that would prevent multiple pieces being joined together into one drawing call. For instance, if a subclass of PangoRenderer was to add a stipple option for drawing underlines, it needs to call

pango_renderer_part_changed (render, PANGO_RENDER_PART_UNDERLINE);

When the stipple changes or underlines with different stipples might be joined together. Pango automatically calls this for changes to colors. (See Renderer.set_color)

Parameters:

part — the part for which rendering has changed.

do_prepare_run¶

def do_prepare_run(self, run: LayoutRun) -> None

updates the renderer for a new run