Rich text and the anti-aliased canvas

[Jean Bréfort <jean brefort ac-dijon fr>]

Hi,

I have written some code to support the Rich Text Item in the 
anti-aliased canvas. My code is probably far from perfect since it uses 
mostly the same things than for the normal canvas but it seems to work.
I intend to use it for GChemPaint.

Best regards

Jean Bréfort

--- gnome-canvas-rich-text.c.orig	Fri Apr 25 16:05:12 2003
+++ gnome-canvas-rich-text.c.new	Fri Apr 25 16:09:28 2003
@@ -2087,11 +2087,90 @@
 } /* gnome_canvas_rich_text_draw */
 
 static void
 gnome_canvas_rich_text_render(GnomeCanvasItem *item, GnomeCanvasBuf *buf)
 {
-	g_warning ("rich text item not implemented for anti-aliased canvas");
+	GnomeCanvasRichText *text = GNOME_CANVAS_RICH_TEXT (item);
+	int x, y, i, r;
+	double x0, y0, h, w;
+	guchar* data;
+	double i2w[6], w2c[6], i2c[6];
+	double ax, ay;
+	double x1, y1, x2, y2;
+	ArtPoint ip, cp;
+
+    gnome_canvas_buf_ensure_buf (buf);
+
+	gnome_canvas_item_i2w_affine(item, i2w);
+	gnome_canvas_w2c_affine(item->canvas, w2c);
+	art_affine_multiply(i2c, i2w, w2c);
+
+	adjust_for_anchors(text, &ax, &ay);
+
+	ip.x = ax;
+	ip.y = ay;
+	art_affine_point(&cp, &ip, i2c);
+	x1 = cp.x;
+	y1 = cp.y;
+
+	ip.x = ax + text->_priv->width;
+	ip.y = ay + text->_priv->height;
+	art_affine_point(&cp, &ip, i2c);
+	x2 = cp.x;
+	y2 = cp.y;
+
+	ip.x = text->_priv->x;
+	ip.y = text->_priv->y;
+	art_affine_point(&cp, &ip, i2c);
+	x0 = cp.x;
+	y0 = cp.y;
+
+	w = x2 - x1;
+	h = y2 - y1;
+	if (x0 < buf->rect.x0)
+	{
+		w -= buf->rect.x0 - x0;
+		x0 = buf->rect.x0;
+		x = 0;
+	}
+	else x = x0 - buf->rect.x0;
+	if (x0 + w >= buf->rect.x1)
+		w = buf->rect.x1 - x0;
+	if (y0 < buf->rect.y0)
+	{
+		h -= buf->rect.y0 - y0;
+		y0 = buf->rect.y0;
+		y = 0;
+	}
+	else y = y0 - buf->rect.y0;
+	if (y0 + h >= buf->rect.y1)
+		h = buf->rect.y1 - y0;
+	if (((int) w == 0) || ((int) h == 0)) return;
+	GdkPixbuf *pxb = gdk_pixbuf_new_from_data (buf->buf + y * buf->buf_rowstride + x * 3,
+																GDK_COLORSPACE_RGB, FALSE, 8, (int) w, (int) h,
+																buf->buf_rowstride, NULL, NULL);
+	GdkPixmap* pb = gdk_pixmap_new (item->canvas->layout.bin_window, (int) w, (int) h, gtk_widget_get_visual ((GtkWidget*) item->canvas)->depth);
+	GdkGC* gc = gdk_gc_new (pb);
+	gdk_pixbuf_render_to_drawable (pxb, pb, gc, 0, 0, 0, 0, w, h, GDK_RGB_DITHER_NONE, 0, 0);
+	gtk_text_layout_set_screen_width(text->_priv->layout, x2 - x1);
+        /* FIXME: should last arg be NULL? */
+	gtk_text_layout_draw(
+		text->_priv->layout,
+		GTK_WIDGET(item->canvas),
+		pb,
+		GTK_WIDGET (item->canvas)->style->text_gc[GTK_STATE_NORMAL],
+		x0 - x1, y0 - y1,
+		0, 0, x2 - x0, y2 - y0,
+		NULL);
+
+	GdkPixbuf* pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, FALSE, 8, (int) w, (int) h);
+	GdkColormap* map = gdk_colormap_new (gtk_widget_get_visual ((GtkWidget*) item->canvas), FALSE);
+	gdk_pixbuf_get_from_drawable (pixbuf, pb, map, 0, 0, 0, 0, (int) w, (int) h);
+	data = gdk_pixbuf_get_pixels (pixbuf);
+	r = gdk_pixbuf_get_rowstride (pixbuf);
+	for (i = 0; i < h; i++)
+		memcpy (buf->buf + (y + i) * buf->buf_rowstride + x * 3, data + i * r, (int) w * 3);
 } /* gnome_canvas_rich_text_render */
 
 #if 0
 static GtkTextTag *
 gnome_canvas_rich_text_add_tag(GnomeCanvasRichText *text, char *tag_name,