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Pango Reference Manual | |
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PangoRenderer;
enum PangoRenderPart;
#define PANGO_TYPE_RENDER_PART
PangoRendererClass;
void pango_renderer_draw_layout (PangoRenderer *renderer,
PangoLayout *layout,
int x,
int y);
void pango_renderer_draw_layout_line (PangoRenderer *renderer,
PangoLayoutLine *line,
int x,
int y);
void pango_renderer_draw_glyphs (PangoRenderer *renderer,
PangoFont *font,
PangoGlyphString *glyphs,
int x,
int y);
void pango_renderer_draw_rectangle (PangoRenderer *renderer,
PangoRenderPart part,
int x,
int y,
int width,
int height);
void pango_renderer_draw_error_underline
(PangoRenderer *renderer,
int x,
int y,
int width,
int height);
void pango_renderer_draw_trapezoid (PangoRenderer *renderer,
PangoRenderPart part,
double y1_,
double x11,
double x21,
double y2,
double x12,
double x22);
void pango_renderer_draw_glyph (PangoRenderer *renderer,
PangoFont *font,
PangoGlyph glyph,
double x,
double y);
void pango_renderer_activate (PangoRenderer *renderer);
void pango_renderer_deactivate (PangoRenderer *renderer);
void pango_renderer_part_changed (PangoRenderer *renderer,
PangoRenderPart part);
void pango_renderer_set_color (PangoRenderer *renderer,
PangoRenderPart part,
const PangoColor *color);
PangoColor* pango_renderer_get_color (PangoRenderer *renderer,
PangoRenderPart part);
void pango_renderer_set_matrix (PangoRenderer *renderer,
const PangoMatrix *matrix);
const PangoMatrix* pango_renderer_get_matrix
(PangoRenderer *renderer);
PangoRenderer is a base class that contains the necessary logic for
rendering a PangoLayout or PangoLayoutLine. By subclassing
PangoRenderer and overriding operations such as draw_glyphs and
draw_rectangle, renderers for particular font backends and
destinations can be created.
typedef struct {
PangoMatrix *matrix; /* May be NULL */
} PangoRenderer;
PangoRenderer is a base class for objects that are used to render Pango objects such as PangoGlyphString and PangoLayout.
PangoMatrix *matrix; |
the current transformation matrix for the Renderer; may
be NULL, which should be treated the same as the identity matrix.
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Since 1.8
typedef enum
{
PANGO_RENDER_PART_FOREGROUND,
PANGO_RENDER_PART_BACKGROUND,
PANGO_RENDER_PART_UNDERLINE,
PANGO_RENDER_PART_STRIKETHROUGH
} PangoRenderPart;
PangoRenderPart defines different items to render for such purposes as setting colors.
PANGO_RENDER_PART_FOREGROUND |
the text itself |
PANGO_RENDER_PART_BACKGROUND |
the area behind the text |
PANGO_RENDER_PART_UNDERLINE |
underlines |
PANGO_RENDER_PART_STRIKETHROUGH |
strikethrough lines |
Since 1.8
#define PANGO_TYPE_RENDER_PART (pango_render_part_get_type())
The GObject type for PangoRenderPart.
typedef struct {
/* All of the following have default implementations
* and take as coordinates user coordinates in Pango units
*/
void (*draw_glyphs) (PangoRenderer *renderer,
PangoFont *font,
PangoGlyphString *glyphs,
int x,
int y);
void (*draw_rectangle) (PangoRenderer *renderer,
PangoRenderPart part,
int x,
int y,
int width,
int height);
void (*draw_error_underline) (PangoRenderer *renderer,
int x,
int y,
int width,
int height);
/* Nothing is drawn for shaped glyphs unless this is implemented */
void (*draw_shape) (PangoRenderer *renderer,
PangoAttrShape *attr,
int x,
int y);
/* These two must be implemented and take coordinates in
* device space as doubles.
*/
void (*draw_trapezoid) (PangoRenderer *renderer,
PangoRenderPart part,
double y1_,
double x11,
double x21,
double y2,
double x12,
double x22);
void (*draw_glyph) (PangoRenderer *renderer,
PangoFont *font,
PangoGlyph glyph,
double x,
double y);
/* Notification of change in rendering attributes
*/
void (*part_changed) (PangoRenderer *renderer,
PangoRenderPart part);
/* Paired around drawing operations
*/
void (*begin) (PangoRenderer *renderer);
void (*end) (PangoRenderer *renderer);
/* Hooks into the details of layout rendering
*/
void (*prepare_run) (PangoRenderer *renderer,
PangoLayoutRun *run);
} PangoRendererClass;
Class structure for PangoRenderer.
draw_glyphs () |
draws a PangoGlyphString |
draw_rectangle () |
draws a rectangle |
draw_error_underline () |
draws a squiggly line that approximately covers the given rectangle in the style of an underline used to indicate a spelling error. |
draw_shape () |
draw content for a glyph shaped with PangoAttrShape.
x, y are the coordinates of the left edge of the baseline,
in user coordinates.
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draw_trapezoid () |
draws a trapezoidal filled area |
draw_glyph () |
draws a single glyph |
part_changed () |
do renderer specific processing when rendering attributes change |
begin () |
Do renderer-specific initialization before drawing |
end () |
Do renderer-specific cleanup after drawing |
prepare_run () |
updates the renderer for a new run |
Since 1.8
void pango_renderer_draw_layout (PangoRenderer *renderer, PangoLayout *layout, int x, int y);
Draws layout with the specified PangoRenderer.
renderer : |
a PangoRenderer |
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. |
Since 1.8
void pango_renderer_draw_layout_line (PangoRenderer *renderer, PangoLayoutLine *line, int x, int y);
Draws line with the specified PangoRenderer.
renderer : |
a PangoRenderer |
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. |
Since 1.8
void pango_renderer_draw_glyphs (PangoRenderer *renderer, PangoFont *font, PangoGlyphString *glyphs, int x, int y);
Draws the glyphs in glyphs with the specified PangoRenderer.
renderer : |
a PangoRenderer |
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. |
Since 1.8
void pango_renderer_draw_rectangle (PangoRenderer *renderer, PangoRenderPart part, int x, int y, int width, int height);
Draws an axis-aligned rectangle in user space coordinates with the specified PangoRenderer.
This should be called while renderer is already active. Use
pango_renderer_activate() to activate a renderer.
renderer : |
a PangoRenderer |
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 in user space coordinates |
height : |
height of rectangle in Pango units in user space coordinates |
Since 1.8
void pango_renderer_draw_error_underline
(PangoRenderer *renderer,
int x,
int y,
int width,
int height);
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
pango_renderer_activate() to activate a renderer.
renderer : |
a PangoRenderer |
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 |
Since 1.8
void pango_renderer_draw_trapezoid (PangoRenderer *renderer, PangoRenderPart part, double y1_, double x11, double x21, double y2, double x12, double x22);
Draws a trapezoid with the parallel sides aligned with the X axis using the given PangoRenderer; coordinates are in device space.
renderer : |
a PangoRenderer |
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 |
Since 1.8
void pango_renderer_draw_glyph (PangoRenderer *renderer, PangoFont *font, PangoGlyph glyph, double x, double y);
Draws a single glyph with coordinates in device space.
renderer : |
a PangoRenderer |
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 |
Since 1.8
void pango_renderer_activate (PangoRenderer *renderer);
Does initial setup before rendering operations on renderer.
pango_renderer_deactivate() should be called when done drawing.
Calls such as pango_renderer_draw_layout() automatically
activate the layout before drawing on it. Calls to
pango_renderer_activate() and pango_renderer_deactivate() can
be nested and the renderer will only be initialized and
deinitialized once.
renderer : |
a PangoRenderer |
Since 1.8
void pango_renderer_deactivate (PangoRenderer *renderer);
Cleans up after rendering operations on renderer. See
docs for pango_renderer_activate().
renderer : |
a PangoRenderer |
Since 1.8
void pango_renderer_part_changed (PangoRenderer *renderer, PangoRenderPart part);
Informs Pango that the way that the rendering is done
for part has changed 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 pango_renderer_set_color())
renderer : |
a PangoRenderer |
part : |
the part for which rendering has changed. |
Since 1.8
void pango_renderer_set_color (PangoRenderer *renderer, PangoRenderPart part, const PangoColor *color);
Sets the color for part of the rendering.
renderer : |
a PangoRenderer |
part : |
the part to change the color of |
color : |
the new color or NULL to unset the current color
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Since 1.8
PangoColor* pango_renderer_get_color (PangoRenderer *renderer, PangoRenderPart part);
Gets the current rendering color for the specified part.
renderer : |
a PangoRenderer |
part : |
the part to get the color for |
| Returns : | the color for the specified part, or NULL
if it hasn't been set and should be inherited from the
environment.
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Since 1.8
void pango_renderer_set_matrix (PangoRenderer *renderer, const PangoMatrix *matrix);
Sets the transformation matrix that will be applied when rendering.
renderer : |
a PangoRenderer |
matrix : |
a PangoMatrix, or NULL to unset any existing matrix.
(No matrix set is the same as setting the identity matrix.)
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Since 1.8
const PangoMatrix* pango_renderer_get_matrix (PangoRenderer *renderer);
Gets the transformation matrix that will be applied when
rendering. See pango_renderer_set_matrix().
renderer : |
a PangoRenderer |
| Returns : | the matrix, or NULL if no matrix has been set
(which is the same as the identity matrix). The returned
matrix is owned by Pango and must not be modified or
freed.
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Since 1.8