#1553 clip the colors, so we can see which values actually make a dif…

…ference

git-svn-id: https://xpra.org/svn/Xpra/trunk@16331 3bb7dfac-3a0b-4e04-842a-767bc560f471

src/xpra/client/gtk_base/example/colors_gradient.py

@@ -14,43 +14,63 @@ class ColorGradientWindow(gtk.Window):
 
     def __init__(self):
         super(ColorGradientWindow, self).__init__()
+        self.set_title("Color Gradient")
         self.set_position(WIN_POS_CENTER)
         self.set_default_size(1024, 768)
         self.set_app_paintable(True)
         self.set_events(KEY_PRESS_MASK)
+        self.bpc = 16
         if is_gtk3():
             self.connect("draw", self.area_draw)
         else:
             self.connect("expose-event", self.do_expose_event)
+        self.connect("configure_event", self.configure_event)
+        #self.connect('resize', changed)
         self.connect("destroy", gtk.main_quit)
+        self.connect("key_press_event", self.on_key_press)
         self.show_all()
 
+    def configure_event(self, *args):
+        self.queue_draw()
+
+    def on_key_press(self, *args):
+        self.bpc = ((self.bpc-2) % 16)+1
+        self.queue_draw()
+
     def do_expose_event(self, *args):
+        #print("do_expose_event")
         cr = self.get_window().cairo_create()
         self.area_draw(self, cr)
 
     def area_draw(self, widget, cr):
-        #Clear everything:
         cr.save()
         cr.set_operator(cairo.OPERATOR_CLEAR)
         w, h = widget.get_size()
         cr.rectangle(0, 0, w, h)
         cr.fill()
         cr.restore()
 
-        count = 11
-        self.index = 0
-        bh = h//count
-        def paint_block(R=255, G=255, B=255, label=""):
-            y = h*self.index//count
+        blocks = 12
+        bh = h//blocks
+        M = 2**16-1
+        mask = 0
+        for i in range(16-self.bpc):
+            mask = mask*2+1
+        mask = 0xffff ^ mask
+        def normv(v):
+            assert 0<=v<=M
+            iv = int(v) & mask
+            return max(0, float(iv)/M)
+        def paint_block(R=M, G=M, B=M, label=""):
+            y = h*self.index//blocks
             self.index += 1
             cr.set_operator(cairo.OPERATOR_SOURCE)
             for i in range(w):
                 v = float(i)/float(w)
                 cr.save()
-                r = max(0, float(R)*v/255.0)
-                g = max(0, float(G)*v/255.0)
-                b = max(0, float(B)*v/255.0)
+                r = normv(R*v)
+                g = normv(G*v)
+                b = normv(B*v)
                 cr.set_source_rgb(r, g, b)
                 cr.rectangle(i, y, 1, bh)
                 cr.fill()
@@ -61,19 +81,33 @@ def paint_block(R=255, G=255, B=255, label=""):
                 cr.move_to(w//2-12, y+bh//2+8)
                 cr.show_text(label)
 
-        paint_block(255, 0, 0, "R")
-        paint_block(0, 254, 0, "G")
-        paint_block(0, 0, 253, "B")
-        paint_block(0, 252, 252, "C")
-        paint_block(251, 0, 251, "M")
-        paint_block(251, 251, 0, "Y")
+        #top block for title, all white:
+        cr.save()
+        cr.set_source_rgb(1, 1, 1)
+        cr.rectangle(0, 0, w, bh)
+        cr.fill()
+        cr.restore()
+        #title
+        cr.set_font_size(32)
+        cr.set_source_rgb(0, 0, 0)
+        txt = "Clipped to %i bytes per pixel" % self.bpc
+        cr.move_to(w//2-8*len(txt), bh//2+8)
+        cr.show_text(txt)
+
+        self.index = 1
+        paint_block(M, 0, 0, "R")
+        paint_block(0, M-1, 0, "G")
+        paint_block(0, 0, M-2, "B")
+        paint_block(0, M-3, M-3, "C")
+        paint_block(M-4, 0, M-4, "M")
+        paint_block(M-5, M-5, 0, "Y")
         paint_block(0, 0, 0, "K")
         #Black Shade Blocks:
-        paint_block(255, 255, 255)
-        paint_block(127, 127, 127)
-        paint_block(63, 63, 63)
-        paint_block(31, 31, 31)
-        paint_block(15, 15, 15)
+        paint_block(M, M, M)
+        paint_block(M//2, M//2, M//2)
+        paint_block(M//4, M//4, M//4)
+        paint_block(M//8, M//8, M//8)
+        paint_block(M//16, M//16, M//16)
 
 
 def main():