--- /dev/null
+/*
+ * 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 <math.h>
+
+#include <pango/pango.h>
+#include <cairo/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 gboolean
+_pango_cairo_font_install (PangoFont *font,
+ cairo_t *cr)
+{
+ cairo_scaled_font_t *scaled_font = pango_cairo_font_get_scaled_font ((PangoCairoFont *)font);
+
+ if (G_UNLIKELY (scaled_font == NULL || cairo_scaled_font_status (scaled_font) != CAIRO_STATUS_SUCCESS))
+ return FALSE;
+
+ cairo_set_scaled_font (cr, scaled_font);
+
+ return TRUE;
+}
+
+static void
+gsk_pango_renderer_draw_unknown_glyph (GskPangoRenderer *crenderer,
+ PangoFont *font,
+ PangoGlyphInfo *gi,
+ double cx,
+ double cy)
+{
+ cairo_t *cr;
+ PangoGlyphString *glyphs;
+
+ cr = gtk_snapshot_append_cairo (crenderer->snapshot, &crenderer->bounds, "DrawUnknownGlyph<%u>", gi->glyph);
+
+ gdk_cairo_set_source_rgba (cr, &crenderer->fg_color);
+
+ cairo_move_to (cr, cx, cy);
+
+ glyphs = pango_glyph_string_new ();
+ pango_glyph_string_set_size (glyphs, 1);
+ glyphs->glyphs[0] = *gi;
+
+ pango_cairo_show_glyph_string (cr, font, glyphs);
+
+ cairo_destroy (cr);
+}
+
+#ifndef STACK_BUFFER_SIZE
+#define STACK_BUFFER_SIZE (512 * sizeof (int))
+#endif
+
+#define STACK_ARRAY_LENGTH(T) (STACK_BUFFER_SIZE / sizeof(T))
+
+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);
+
+ cairo_t *cr;
+ int i, count;
+ int x_position = 0;
+ cairo_glyph_t *cairo_glyphs;
+ cairo_glyph_t stack_glyphs[STACK_ARRAY_LENGTH (cairo_glyph_t)];
+ double base_x = crenderer->x_offset + (double)x / PANGO_SCALE;
+ double base_y = crenderer->y_offset + (double)y / PANGO_SCALE;
+
+ cr = gtk_snapshot_append_cairo (crenderer->snapshot, &crenderer->bounds, "Text<%dglyphs>", glyphs->num_glyphs);
+
+ set_color (crenderer, PANGO_RENDER_PART_FOREGROUND, cr);
+
+ if (!_pango_cairo_font_install (font, cr))
+ {
+ for (i = 0; i < glyphs->num_glyphs; i++)
+ {
+ PangoGlyphInfo *gi = &glyphs->glyphs[i];
+
+ if (gi->glyph != PANGO_GLYPH_EMPTY)
+ {
+ double cx = base_x + (double)(x_position + gi->geometry.x_offset) / PANGO_SCALE;
+ double cy = gi->geometry.y_offset == 0 ?
+ base_y :
+ base_y + (double)(gi->geometry.y_offset) / PANGO_SCALE;
+
+ gsk_pango_renderer_draw_unknown_glyph (crenderer, font, gi, cx, cy);
+ }
+ x_position += gi->geometry.width;
+ }
+
+ goto done;
+ }
+
+ if (glyphs->num_glyphs > (int) G_N_ELEMENTS (stack_glyphs))
+ cairo_glyphs = g_new (cairo_glyph_t, glyphs->num_glyphs);
+ else
+ cairo_glyphs = stack_glyphs;
+
+ count = 0;
+ for (i = 0; i < glyphs->num_glyphs; i++)
+ {
+ PangoGlyphInfo *gi = &glyphs->glyphs[i];
+
+ if (gi->glyph != PANGO_GLYPH_EMPTY)
+ {
+ double cx = base_x + (double)(x_position + gi->geometry.x_offset) / PANGO_SCALE;
+ double cy = gi->geometry.y_offset == 0 ?
+ base_y :
+ base_y + (double)(gi->geometry.y_offset) / PANGO_SCALE;
+
+ if (gi->glyph & PANGO_GLYPH_UNKNOWN_FLAG)
+ gsk_pango_renderer_draw_unknown_glyph (crenderer, font, gi, cx, cy);
+ else
+ {
+ cairo_glyphs[count].index = gi->glyph;
+ cairo_glyphs[count].x = cx;
+ cairo_glyphs[count].y = cy;
+ count++;
+ }
+ }
+ x_position += gi->geometry.width;
+ }
+
+ if (G_UNLIKELY (clusters))
+ cairo_show_text_glyphs (cr,
+ text, text_len,
+ cairo_glyphs, count,
+ clusters, num_clusters,
+ backward ? CAIRO_TEXT_CLUSTER_FLAG_BACKWARD : 0);
+ else
+ cairo_show_glyphs (cr, cairo_glyphs, count);
+
+ if (cairo_glyphs != stack_glyphs)
+ g_free (cairo_glyphs);
+
+done:
+ cairo_destroy (cr);
+}
+
+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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