commit 34c49b24920274455f2784b2ae6ac9108b226856
Author: Thomas Lübking <thomas.luebking@gmail.com>
Date:   Mon Nov 17 20:09:03 2014 +0100

    simplify format selection, make 24bit rgb32
    
    an image w/o alphachannel is certainly not
    premultiplied
    
    the findFormat() made not much sense at all
    it was only used if the image depth was
    the default depth and then looked up supported
    16, 24 and 32 bit formats
    
    However 32 bit images were handled before
    unconditionally so this was only relevant for
    16 bit images (where we supported either 5-6-5
    or nothing) or 24bit images, where a false value
    (ARGB_premultiplied implies 32bit) was returned.
    
    IOW: for the majority of images (32bit) this was
    not used, for 24bpp displays we got a falsely
    colored images and for 16bpp either a correctly
    colored (for 5-6-5 layouts) or no image at all
    (for 5-5-5 or [4-]4-4-4 layouts)
    
    I don't know whether 16bpp w/ 5-5-5 or 4-4-4 itw.,
    but better show them miscolored images (and trigger
    a bug) than none.
    If there're funky 24bpp servers (other than 8-8-8)
    somebody shall please report a bug to us.
    
    Possible TODO:
    add a single call to test the server layout (channel
    masks) and yell an error if there's something "strange"
    
    BUG: 340348

diff --git a/src/kxutils.cpp b/src/kxutils.cpp
index c75c08e..015749d 100644
--- src/kxutils.cpp
+++ src/kxutils.cpp
@@ -30,57 +30,6 @@
 namespace KXUtils
 {
 
-static uint8_t defaultDepth()
-{
-    xcb_connection_t *c = QX11Info::connection();
-    int screen = QX11Info::appScreen();
-
-    xcb_screen_iterator_t it = xcb_setup_roots_iterator(xcb_get_setup(c));
-    for (; it.rem; --screen, xcb_screen_next(&it)) {
-        if (screen == 0) {
-            return it.data->root_depth;
-        }
-    }
-    return 0;
-}
-
-static QImage::Format findFormat()
-{
-    xcb_connection_t *c = QX11Info::connection();
-    int screen = QX11Info::appScreen();
-
-    xcb_screen_iterator_t screenIt = xcb_setup_roots_iterator(xcb_get_setup(c));
-    for (; screenIt.rem; --screen, xcb_screen_next(&screenIt)) {
-        if (screen != 0) {
-            continue;
-        }
-        xcb_depth_iterator_t depthIt = xcb_screen_allowed_depths_iterator(screenIt.data);
-        for (; depthIt.rem; xcb_depth_next(&depthIt)) {
-            xcb_visualtype_iterator_t visualIt = xcb_depth_visuals_iterator(depthIt.data);
-            for (; visualIt.rem; xcb_visualtype_next(&visualIt)) {
-                if (screenIt.data->root_visual != visualIt.data->visual_id) {
-                    continue;
-                }
-                xcb_visualtype_t *visual = visualIt.data;
-                if ((depthIt.data->depth == 24 || depthIt.data->depth == 32) &&
-                        visual->red_mask   == 0x00ff0000 &&
-                        visual->green_mask == 0x0000ff00 &&
-                        visual->blue_mask  == 0x000000ff) {
-                    return QImage::Format_ARGB32_Premultiplied;
-                }
-                if (depthIt.data->depth == 16 &&
-                        visual->red_mask   == 0xf800 &&
-                        visual->green_mask == 0x07e0 &&
-                        visual->blue_mask  == 0x001f) {
-                    return QImage::Format_RGB16;
-                }
-                break;
-            }
-        }
-    }
-    return QImage::Format_Invalid;
-}
-
 template <typename T> T fromNative(xcb_pixmap_t pixmap)
 {
     xcb_connection_t *c = QX11Info::connection();
@@ -99,11 +48,17 @@ template <typename T> T fromNative(xcb_pixmap_t pixmap)
         // request for image data failed
         return T();
     }
-    QImage::Format format = QImage::Format_ARGB32_Premultiplied;
+    QImage::Format format = QImage::Format_Invalid;
     switch (xImage->depth) {
     case 1:
         format = QImage::Format_MonoLSB;
         break;
+    case 16:
+        format = QImage::Format_RGB16;
+        break;
+    case 24:
+        format = QImage::Format_RGB32;
+        break;
     case 30: {
         // Qt doesn't have a matching image format. We need to convert manually
         uint32_t *pixels = reinterpret_cast<uint32_t *>(xcb_get_image_data(xImage.data()));
@@ -120,15 +75,7 @@ template <typename T> T fromNative(xcb_pixmap_t pixmap)
         format = QImage::Format_ARGB32_Premultiplied;
         break;
     default:
-        if (xImage->depth == defaultDepth()) {
-            format = findFormat();
-            if (format == QImage::Format_Invalid) {
-                return T();
-            }
-        } else {
-            // we don't know
-            return T();
-        }
+        return T(); // we don't know
     }
     QImage image(xcb_get_image_data(xImage.data()), geo->width, geo->height,
                  xcb_get_image_data_length(xImage.data()) / geo->height, format, free, xImage.data());