+ // Much of this code is copied from the font-pangoft2.c example that comes with GtkGLExt.
+
+ PangoLayout *layout;
+ PangoRectangle ink_rect;
+ PangoRectangle log_rect;
+ FT_Bitmap bitmap;
+ GLvoid *pixels;
+ guint32 *p;
+ GLfloat color[4];
+ guint32 rgb;
+ GLfloat alpha;
+ guint8 *row, *row_end;
+ int i;
+ GLint previous_unpack_alignment;
+ GLboolean previous_blend_enabled;
+ GLint previous_blend_src;
+ GLint previous_blend_dst;
+
+
+ if (!_debug_font_created) {
+ Error("Programming error: gtk_glwidget_print_string() called but font does not exist; "
+ "you should have called gtk_glwidget_create_font() first");
+ }
+
+ layout = pango_layout_new(ft2_context);
+ pango_layout_set_width(layout, -1); // -1 no wrapping. All text on one line.
+ pango_layout_set_text(layout, s, -1); // -1 null-terminated string.
+ pango_layout_get_extents(layout, &ink_rect, &log_rect);
+
+ if (log_rect.width > 0 && log_rect.height > 0) {
+ bitmap.rows = font_ascent + font_descent;
+ bitmap.width = PANGO_PIXELS_CEIL(log_rect.width);
+ bitmap.pitch = bitmap.width;
+ bitmap.buffer = g_malloc(bitmap.rows * bitmap.width);
+ bitmap.num_grays = 0xff;
+ bitmap.pixel_mode = FT_PIXEL_MODE_GRAY;
+ memset(bitmap.buffer, 0, bitmap.rows * bitmap.width);
+ pango_ft2_render_layout_subpixel(&bitmap, layout, -log_rect.x,
+ y_offset_bitmap_render_pango_units);
+
+ pixels = g_malloc(bitmap.rows * bitmap.width * 4);
+ p = (guint32 *) pixels;
+ qglGetFloatv(GL_CURRENT_COLOR, color);
+#if !defined(GL_VERSION_1_2) && G_BYTE_ORDER == G_LITTLE_ENDIAN
+ rgb =
+ (((guint32) (color[0] * 255.0)) << 0) |
+ (((guint32) (color[1] * 255.0)) << 8) |
+ (((guint32) (color[2] * 255.0)) << 16);
+#else
+ rgb =
+ (((guint32) (color[0] * 255.0)) << 24) |
+ (((guint32) (color[1] * 255.0)) << 16) |
+ (((guint32) (color[2] * 255.0)) << 8);
+#endif
+ alpha = color[3];
+
+ row = bitmap.buffer + bitmap.rows * bitmap.width; // Past the end.
+ row_end = bitmap.buffer; // Beginning.
+
+ if (alpha == 1.0) {
+ do {
+ row -= bitmap.width;
+ for (i = 0; i < bitmap.width; i++) {
+#if !defined(GL_VERSION_1_2) && G_BYTE_ORDER == G_LITTLE_ENDIAN
+ *p++ = rgb | (((guint32) row[i]) << 24);
+#else
+ *p++ = rgb | ((guint32) row[i]);
+#endif
+ }
+ } while (row != row_end);
+ }
+
+ else { // Translucent. Much less efficient, so try to avoid.
+ do {
+ row -= bitmap.width;
+ for (i = 0; i < bitmap.width; i++) {
+#if !defined(GL_VERSION_1_2) && G_BYTE_ORDER == G_LITTLE_ENDIAN
+ *p++ = rgb | (((guint32) (alpha * row[i])) << 24);
+#else
+ *p++ = rgb | ((guint32) (alpha * row[i]));
+#endif
+ }
+ } while (row != row_end);
+ }
+
+ // Save state. I didn't see any OpenGL push/pop operations for these.
+ // Question: Is saving/restoring this state necessary?
+ qglGetIntegerv(GL_UNPACK_ALIGNMENT, &previous_unpack_alignment);
+ previous_blend_enabled = qglIsEnabled(GL_BLEND);
+ qglGetIntegerv(GL_BLEND_SRC, &previous_blend_src);
+ qglGetIntegerv(GL_BLEND_DST, &previous_blend_dst);
+
+ qglPixelStorei(GL_UNPACK_ALIGNMENT, 4);
+ qglEnable(GL_BLEND);
+ qglBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
+#if !defined(GL_VERSION_1_2)
+ qglDrawPixels(bitmap.width, bitmap.rows,
+ GL_RGBA, GL_UNSIGNED_BYTE, pixels);
+#else
+ qglDrawPixels(bitmap.width, bitmap.rows,
+ GL_RGBA, GL_UNSIGNED_INT_8_8_8_8, pixels);
+#endif
+
+ // Restore state in reverse order of how we set it.
+ qglBlendFunc(previous_blend_src, previous_blend_dst);
+ if (!previous_blend_enabled) { qglDisable(GL_BLEND); }
+ qglPixelStorei(GL_UNPACK_ALIGNMENT, previous_unpack_alignment);
+
+ g_free(bitmap.buffer);
+ g_free(pixels);
+ }
+
+ g_object_unref(G_OBJECT(layout));