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gtk2/gtk/gskpango.c
Timm Bäder 8a062f4f9a gskpango: Don't create text nodes for clipped text 
Measure the text here directly and check if the created node bounds will
be clipped away before even creating the text node.
2018-03-04 19:15:03 +01:00

462 lines
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/*
* Copyright (C) 2017 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include "config.h"
#include "gsk/gsk.h"
#include "gskpango.h"
#include "gtksnapshotprivate.h"
#include <math.h>
#include <pango/pango.h>
#include <cairo.h>
#define GSK_PANGO_RENDERER_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), GSK_TYPE_PANGO_RENDERER, GskPangoRendererClass))
#define GSK_IS_PANGO_RENDERER_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GSK_TYPE_PANGO_RENDERER))
#define GSK_PANGO_RENDERER_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), GSK_TYPE_PANGO_RENDERER, GskPangoRendererClass))
/*
* This is a PangoRenderer implementation that translates all the draw calls to
* gsk render nodes, using the GtkSnapshot helper class. Glyphs are translated
* to text nodes, all other draw calls fall back to cairo nodes.
*/
struct _GskPangoRenderer
{
PangoRenderer parent_instance;
GtkSnapshot *snapshot;
GdkRGBA fg_color;
graphene_rect_t bounds;
/* house-keeping options */
gboolean is_cached_renderer;
};
struct _GskPangoRendererClass
{
PangoRendererClass parent_class;
};
G_DEFINE_TYPE (GskPangoRenderer, gsk_pango_renderer, PANGO_TYPE_RENDERER)
static void
get_color (GskPangoRenderer *crenderer,
PangoRenderPart part,
GdkRGBA *rgba)
{
PangoColor *color = pango_renderer_get_color ((PangoRenderer *) (crenderer), part);
guint16 a = pango_renderer_get_alpha ((PangoRenderer *) (crenderer), part);
gdouble red, green, blue, alpha;
red = crenderer->fg_color.red;
green = crenderer->fg_color.green;
blue = crenderer->fg_color.blue;
alpha = crenderer->fg_color.alpha;
if (color)
{
red = color->red / 65535.;
green = color->green / 65535.;
blue = color->blue / 65535.;
alpha = 1.;
}
if (a)
alpha = a / 65535.;
rgba->red = red;
rgba->green = green;
rgba->blue = blue;
rgba->alpha = alpha;
}
static void
set_color (GskPangoRenderer *crenderer,
PangoRenderPart part,
cairo_t *cr)
{
GdkRGBA rgba = { 0, 0, 0, 1 };
get_color (crenderer, part, &rgba);
gdk_cairo_set_source_rgba (cr, &rgba);
}
static void
gsk_pango_renderer_show_text_glyphs (PangoRenderer *renderer,
const char *text,
int text_len,
PangoGlyphString *glyphs,
cairo_text_cluster_t *clusters,
int num_clusters,
gboolean backward,
PangoFont *font,
int x,
int y)
{
GskPangoRenderer *crenderer = (GskPangoRenderer *) (renderer);
int x_offset, y_offset;
GskRenderNode *node;
GdkRGBA color;
graphene_rect_t node_bounds;
PangoRectangle ink_rect;
pango_glyph_string_extents (glyphs, font, &ink_rect, NULL);
pango_extents_to_pixels (&ink_rect, NULL);
/* Don't create empty nodes */
if (ink_rect.width == 0 || ink_rect.height == 0)
return;
gtk_snapshot_get_offset (crenderer->snapshot, &x_offset, &y_offset);
graphene_rect_init (&node_bounds,
x_offset + (float)x/PANGO_SCALE,
y_offset + (float)y/PANGO_SCALE + ink_rect.y,
ink_rect.x + ink_rect.width,
ink_rect.height);
/* Remove the snapshot offset from the position here again since
* gtk_snapshot_clips_rect will apply it to the given rect. */
if (gtk_snapshot_clips_rect (crenderer->snapshot,
&(cairo_rectangle_int_t){
node_bounds.origin.x - x_offset,
node_bounds.origin.y - y_offset,
ceil (node_bounds.size.width),
ceil (node_bounds.size.height)
}))
return;
get_color (crenderer, PANGO_RENDER_PART_FOREGROUND, &color);
node = gsk_text_node_new_with_bounds (font,
glyphs,
&color,
x_offset + (double)x/PANGO_SCALE,
y_offset + (double)y/PANGO_SCALE,
&node_bounds);
if (node == NULL)
return;
if (crenderer->snapshot->record_names)
{
char name[64];
g_snprintf (name, sizeof (name), "Glyphs<%d>", glyphs->num_glyphs);
gsk_render_node_set_name (node, name);
}
gtk_snapshot_append_node (crenderer->snapshot, node);
gsk_render_node_unref (node);
}
static void
gsk_pango_renderer_draw_glyphs (PangoRenderer *renderer,
PangoFont *font,
PangoGlyphString *glyphs,
int x,
int y)
{
gsk_pango_renderer_show_text_glyphs (renderer, NULL, 0, glyphs, NULL, 0, FALSE, font, x, y);
}
static void
gsk_pango_renderer_draw_glyph_item (PangoRenderer *renderer,
const char *text,
PangoGlyphItem *glyph_item,
int x,
int y)
{
PangoFont *font = glyph_item->item->analysis.font;
PangoGlyphString *glyphs = glyph_item->glyphs;
gsk_pango_renderer_show_text_glyphs (renderer, NULL, 0, glyphs, NULL, 0, FALSE, font, x, y);
}
static void
gsk_pango_renderer_draw_rectangle (PangoRenderer *renderer,
PangoRenderPart part,
int x,
int y,
int width,
int height)
{
GskPangoRenderer *crenderer = (GskPangoRenderer *) (renderer);
GdkRGBA rgba;
graphene_rect_t bounds;
get_color (crenderer, part, &rgba);
graphene_rect_init (&bounds,
(double)x / PANGO_SCALE, (double)y / PANGO_SCALE,
(double)width / PANGO_SCALE, (double)height / PANGO_SCALE);
gtk_snapshot_append_color (crenderer->snapshot, &rgba, &bounds, "DrawRectangle");
}
static void
gsk_pango_renderer_draw_trapezoid (PangoRenderer *renderer,
PangoRenderPart part,
double y1_,
double x11,
double x21,
double y2,
double x12,
double x22)
{
GskPangoRenderer *crenderer = (GskPangoRenderer *) (renderer);
cairo_t *cr;
gdouble x, y;
cr = gtk_snapshot_append_cairo (crenderer->snapshot, &crenderer->bounds, "DrawTrapezoid");
set_color (crenderer, part, cr);
x = y = 0;
cairo_user_to_device_distance (cr, &x, &y);
cairo_identity_matrix (cr);
cairo_translate (cr, x, y);
cairo_move_to (cr, x11, y1_);
cairo_line_to (cr, x21, y1_);
cairo_line_to (cr, x22, y2);
cairo_line_to (cr, x12, y2);
cairo_close_path (cr);
cairo_fill (cr);
cairo_destroy (cr);
}
/* Draws an error underline that looks like one of:
* H E H
* /\ /\ /\ /\ /\ -
* A/ \ / \ / \ A/ \ / \ |
* \ \ / \ / /D \ \ / \ |
* \ \/ C \/ / \ \/ C \ | height = HEIGHT_SQUARES * square
* \ /\ F / \ F /\ \ |
* \ / \ / \ / \ \G |
* \ / \ / \ / \ / |
* \/ \/ \/ \/ -
* B B
* |---|
* unit_width = (HEIGHT_SQUARES - 1) * square
*
* The x, y, width, height passed in give the desired bounding box;
* x/width are adjusted to make the underline a integer number of units
* wide.
*/
#define HEIGHT_SQUARES 2.5
static void
draw_error_underline (cairo_t *cr,
double x,
double y,
double width,
double height)
{
double square = height / HEIGHT_SQUARES;
double unit_width = (HEIGHT_SQUARES - 1) * square;
double double_width = 2 * unit_width;
int width_units = (width + unit_width / 2) / unit_width;
double y_top, y_bottom;
double x_left, x_middle, x_right;
int i;
x += (width - width_units * unit_width) / 2;
y_top = y;
y_bottom = y + height;
/* Bottom of squiggle */
x_middle = x + unit_width;
x_right = x + double_width;
cairo_move_to (cr, x - square / 2, y_top + square / 2); /* A */
for (i = 0; i < width_units-2; i += 2)
{
cairo_line_to (cr, x_middle, y_bottom); /* B */
cairo_line_to (cr, x_right, y_top + square); /* C */
x_middle += double_width;
x_right += double_width;
}
cairo_line_to (cr, x_middle, y_bottom); /* B */
if (i + 1 == width_units)
cairo_line_to (cr, x_middle + square / 2, y_bottom - square / 2); /* G */
else if (i + 2 == width_units) {
cairo_line_to (cr, x_right + square / 2, y_top + square / 2); /* D */
cairo_line_to (cr, x_right, y_top); /* E */
}
/* Top of squiggle */
x_left = x_middle - unit_width;
for (; i >= 0; i -= 2)
{
cairo_line_to (cr, x_middle, y_bottom - square); /* F */
cairo_line_to (cr, x_left, y_top); /* H */
x_left -= double_width;
x_middle -= double_width;
}
}
static void
gsk_pango_renderer_draw_error_underline (PangoRenderer *renderer,
int x,
int y,
int width,
int height)
{
GskPangoRenderer *crenderer = (GskPangoRenderer *) (renderer);
cairo_t *cr;
cr = gtk_snapshot_append_cairo (crenderer->snapshot, &crenderer->bounds, "DrawTrapezoid");
set_color (crenderer, PANGO_RENDER_PART_UNDERLINE, cr);
cairo_new_path (cr);
draw_error_underline (cr,
(double)x / PANGO_SCALE, (double)y / PANGO_SCALE,
(double)width / PANGO_SCALE, (double)height / PANGO_SCALE);
cairo_fill (cr);
cairo_destroy (cr);
}
static void
gsk_pango_renderer_draw_shape (PangoRenderer *renderer,
PangoAttrShape *attr,
int x,
int y)
{
GskPangoRenderer *crenderer = (GskPangoRenderer *) (renderer);
cairo_t *cr;
PangoLayout *layout;
PangoCairoShapeRendererFunc shape_renderer;
gpointer shape_renderer_data;
double base_x = (double)x / PANGO_SCALE;
double base_y = (double)y / PANGO_SCALE;
cr = gtk_snapshot_append_cairo (crenderer->snapshot, &crenderer->bounds, "DrawShape");
layout = pango_renderer_get_layout (renderer);
if (!layout)
return;
shape_renderer = pango_cairo_context_get_shape_renderer (pango_layout_get_context (layout),
&shape_renderer_data);
if (!shape_renderer)
return;
set_color (crenderer, PANGO_RENDER_PART_FOREGROUND, cr);
cairo_move_to (cr, base_x, base_y);
shape_renderer (cr, attr, FALSE, shape_renderer_data);
cairo_destroy (cr);
}
static void
gsk_pango_renderer_init (GskPangoRenderer *renderer G_GNUC_UNUSED)
{
}
static void
gsk_pango_renderer_class_init (GskPangoRendererClass *klass)
{
PangoRendererClass *renderer_class = PANGO_RENDERER_CLASS (klass);
renderer_class->draw_glyphs = gsk_pango_renderer_draw_glyphs;
renderer_class->draw_glyph_item = gsk_pango_renderer_draw_glyph_item;
renderer_class->draw_rectangle = gsk_pango_renderer_draw_rectangle;
renderer_class->draw_trapezoid = gsk_pango_renderer_draw_trapezoid;
renderer_class->draw_error_underline = gsk_pango_renderer_draw_error_underline;
renderer_class->draw_shape = gsk_pango_renderer_draw_shape;
}
static GskPangoRenderer *cached_renderer = NULL; /* MT-safe */
G_LOCK_DEFINE_STATIC (cached_renderer);
static GskPangoRenderer *
acquire_renderer (void)
{
GskPangoRenderer *renderer;
if (G_LIKELY (G_TRYLOCK (cached_renderer)))
{
if (G_UNLIKELY (!cached_renderer))
{
cached_renderer = g_object_new (GSK_TYPE_PANGO_RENDERER, NULL);
cached_renderer->is_cached_renderer = TRUE;
}
renderer = cached_renderer;
}
else
{
renderer = g_object_new (GSK_TYPE_PANGO_RENDERER, NULL);
}
return renderer;
}
static void
release_renderer (GskPangoRenderer *renderer)
{
if (G_LIKELY (renderer->is_cached_renderer))
{
renderer->snapshot = NULL;
G_UNLOCK (cached_renderer);
}
else
g_object_unref (renderer);
}
/* convenience wrappers using the default renderer */
void
gsk_pango_show_layout (GtkSnapshot *snapshot,
const GdkRGBA *fg_color,
PangoLayout *layout)
{
GskPangoRenderer *crenderer;
PangoRectangle ink_rect;
g_return_if_fail (snapshot != NULL);
g_return_if_fail (PANGO_IS_LAYOUT (layout));
crenderer = acquire_renderer ();
crenderer->snapshot = snapshot;
crenderer->fg_color = *fg_color;
pango_layout_get_pixel_extents (layout, &ink_rect, NULL);
graphene_rect_init (&crenderer->bounds, ink_rect.x, ink_rect.y, ink_rect.width, ink_rect.height);
pango_renderer_draw_layout (PANGO_RENDERER (crenderer), layout, 0, 0);
release_renderer (crenderer);
}
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