#3837 add plane range dump utility function

xpra/codecs/argb/argb.pxd

@@ -1,10 +1,12 @@
 # This file is part of Xpra.
 # Copyright (C) 2008, 2009 Nathaniel Smith <njs@pobox.com>
-# Copyright (C) 2013-2021 Antoine Martin <antoine@xpra.org>
+# Copyright (C) 2013-2024 Antoine Martin <antoine@xpra.org>
 # Xpra is released under the terms of the GNU GPL v2, or, at your option, any
 # later version. See the file COPYING for details.
 
 cdef argbdata_to_rgba(const unsigned int* argb, const int argb_len)  #pylint: disable=syntax-error
 cdef argbdata_to_rgb(const unsigned int* argb, const int argb_len)
 cdef bgradata_to_rgb(const unsigned int* bgra, const int bgra_len)
 cdef bgradata_to_rgba(const unsigned int* bgra, const int bgra_len)
+
+cdef show_plane_range(name, plane, int width, int stride, int height)

xpra/codecs/argb/argb.pyx

@@ -776,3 +776,20 @@ cdef bitdata_to_rectangles(const unsigned char* bitdata, const int bitdata_len,
             if start<end:
                 rectangles.append((start, y, end-start, 1))
     return rectangles
+
+
+cdef show_plane_range(name, plane, int width, int stride, int height):
+    cdef unsigned char minv = 255
+    cdef unsigned char maxv = 0
+    cdef unsigned char value
+    cdef const unsigned char *plane_buf
+    with buffer_context(plane) as buf:
+        plane_buf = <unsigned char *> (<uintptr_t> int(buf))
+        for y in range(height):
+            for x in range(width):
+                value = plane_buf[y*stride + x]
+                if value < minv:
+                    minv = value
+                if value > maxv:
+                    maxv = value
+    log.info("%s plane: min=%s, max=%s", name, minv, maxv)