restore region merging, but better: only use merged region if it ends…

… up using less resources than many smaller ones

git-svn-id: https://xpra.org/svn/Xpra/trunk@5425 3bb7dfac-3a0b-4e04-842a-767bc560f471

src/xpra/gtk_common/region.py

@@ -19,6 +19,16 @@ def __init__(self, x, y, w, h):
     def __eq__(self, other):
         return self.x==other.x and self.y==other.y and self.width==other.width and self.height==other.height
 
+    def merge(self, x, y, w, h):
+        self.x = min(self.x, x)
+        self.y = min(self.y, y)
+        self.width = max(self.x+self.width, x+w)-self.x
+        self.height = max(self.y+self.height, y+h)-self.y
+
+    def clone(self):
+        return rectangle(self.x, self.y, self.width, self.height)
+
+
 def _contains(regions, x, y, w, h):
     x2 = x+w
     y2 = y+h

src/xpra/server/window_source.py

@@ -626,12 +626,24 @@ def send_full_window_update():
 
         bytes_threshold = ww*wh*self.max_bytes_percent/100
         pixel_count = sum([rect.width*rect.height for rect in regions])
-        if pixel_count+self.small_packet_cost*len(regions)>=bytes_threshold:
+        bytes_cost = pixel_count+self.small_packet_cost*len(regions)
+        if bytes_cost>=bytes_threshold:
             #too many bytes
             send_full_window_update()
             return
-        log("send_delayed_regions: %s regions with %s pixels", len(regions), pixel_count)
 
+        if len(regions)>1:
+            #try to merge all regions to see if we save anything:
+            merged = regions[0].clone()
+            for r in regions[1:]:
+                merged.merge(r.x, r.y, r.width, r.height)
+            merged_pixel_count = merged.width*merged.height
+            merged_bytes_cost = pixel_count+self.small_packet_cost*1
+            if merged_bytes_cost<bytes_cost or merged_pixel_count<pixel_count:
+                #replace with just one region:
+                regions = [merged]
+
+        log("send_delayed_regions: %s regions with %s pixels", len(regions), pixel_count)
         actual_encoding = self.get_best_encoding(True, window, pixel_count, ww, wh, coding)
         if self.must_encode_full_frame(window, actual_encoding):
             #use full screen dimensions: