Ticket #1432: html5-scroll-tmp-canvas.patch

html5/js/Window.js

@@ -864 +864 @@
 }
 
 XpraWindow.prototype.do_paint = function paint(x, y, width, height, coding, img_data, packet_sequence, rowstride, options, decode_callback) {
+        console.log("do_paint:", coding);
         if (this.debug) {
                 console.debug("do_paint("+img_data.length+" bytes of "+("zlib" in options?"zlib ":"")+coding+" data "+width+"x"+height+" at "+x+","+y+") focused="+this.focused);
         }
@@ -986 +987 @@
         }
         else if (coding=="scroll") {
                 this._non_video_paint(coding);
+                var tmp_canvas = document.createElement("canvas");
+                var tmp_canvas_ctx = tmp_canvas.getContext('2d');
+                this.offscreen_canvas_ctx.drawImage(tmp_canvas, 0, 0, this.w, this.h, 0, 0, this.w, this.h);
                 for(var i=0,j=img_data.length;i<j;++i) {
                         var scroll_data = img_data[i];
                         var sx = scroll_data[0],
@@ -994 +998 @@
                                 sh = scroll_data[3],
                                 xdelta = scroll_data[4],
                                 ydelta = scroll_data[5];
-                        this.offscreen_canvas_ctx.drawImage(this.offscreen_canvas, sx, sy, sw, sh, sx+xdelta, y+ydelta, sw, sh);
+                        tmp_canvas_ctx.drawImage(this.offscreen_canvas, sx, sy, sw, sh, sx+xdelta, y+ydelta, sw, sh);
                 }
                 painted();
         }