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gtk2/gtk/gskpango.c
Matthias Clasen b0e8d8483d More work on text nodes 
This commit takes several steps towards rendering text
like we want to.

The creation of the cairo surface and texture is moved
to the backend (in GskVulkanRenderer). We add a mask
shader that is used in the next text pipeline to use
the texture as a mask, like cairo_mask_surface does.
There is a separate color text pipeline that uses the
already existing blend shaders to use the texture as
a source, like cairo_paint does.

The text node api is simplified to have just a single
offset, which determines the left end of the text baseline,
like all our other text drawing APIs.
2017-09-10 14:36:26 -04:00

430 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;
gtk_snapshot_get_offset (crenderer->snapshot, &x_offset, &y_offset);
get_color (crenderer, PANGO_RENDER_PART_FOREGROUND, &color);
node = gsk_text_node_new (font, glyphs, &color, x_offset + (double)x/PANGO_SCALE, y_offset + (double)y/PANGO_SCALE);
if (node == NULL)
return;
if (crenderer->snapshot->record_names)
{
char name[64];
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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