[gdk-pixbuf] ico: Prefer entries with the largest dimensions

[Bastien Nocera <hadess src gnome org>]

commit 91e2d7c80ebd21bce3a0f21741c8075eccc52235
Author: Bastien Nocera <hadess hadess net>
Date:   Wed Dec 14 15:30:56 2016 +0100

    ico: Prefer entries with the largest dimensions
    
    Not the largest data size.

 gdk-pixbuf/io-ico.c |   24 +++++++++++++++++-------
 1 files changed, 17 insertions(+), 7 deletions(-)
---
diff --git a/gdk-pixbuf/io-ico.c b/gdk-pixbuf/io-ico.c
index f5b0c6f..09087e9 100644
--- a/gdk-pixbuf/io-ico.c
+++ b/gdk-pixbuf/io-ico.c
@@ -209,9 +209,9 @@ static void DecodeHeader(guchar *Data, gint Bytes,
                         GError **error)
 {
 /* For ICO's we have to be very clever. There are multiple images possible
-   in an .ICO. As a simple heuristic, we select the image which occupies the 
-   largest number of bytes.
- */   
+   in an .ICO. As a simple heuristic, we select the image which is the largest
+   in pixels.
+ */
        struct ico_direntry_data *entry;
        gint IconCount = 0; /* The number of icon-versions in the file */
        guchar *BIH; /* The DIB for the used icon */
@@ -275,29 +275,39 @@ static void DecodeHeader(guchar *Data, gint Bytes,
        for (I=0;I<IconCount;I++) {
                 int width;
                 int height;
+                int depth;
                 int x_hot;
                 int y_hot;
-                int data_size;
+                int data_size G_GNUC_UNUSED;
                 int data_offset;
 
                 width = Ptr[0];
                 height = Ptr[1];
+                depth = Ptr[2];
                x_hot = (Ptr[5] << 8) + Ptr[4];
                y_hot = (Ptr[7] << 8) + Ptr[6];
                 data_size = (Ptr[11] << 24) + (Ptr[10] << 16) + (Ptr[9] << 8) + (Ptr[8]);
                data_offset = (Ptr[15] << 24) + (Ptr[14] << 16) + (Ptr[13] << 8) + (Ptr[12]);
-                DEBUG(g_print ("Image %d: %d x %d\n\tPalette: %d\n", I, width, height, Ptr[2]);
+                DEBUG(g_print ("Image %d: %d x %d\n\tDepth: %d\n", I, width, height, depth);
                 if (imgtype == 2)
                   g_print ("\tHotspot: %d x %d\n", x_hot, y_hot);
                 else
                   g_print ("\tColor planes: %d\n\tBits per pixel: %d\n", x_hot, y_hot);
                 g_print ("\tSize: %d\n\tOffset: %d\n", data_size, data_offset);)
 
-               entry = g_new0 (struct ico_direntry_data, 1);
-               entry->ImageScore = data_size;
+                if (depth == 0)
+                        depth = 32;
+                else if (depth <= 2)
+                        depth = 1;
+                else if (depth <= 16)
+                        depth = 4;
+                else if (depth <= 256)
+                        depth = 8;
 
+               entry = g_new0 (struct ico_direntry_data, 1);
                 entry->width = width ? width : 256;
                 entry->height = height ? height : 256;
+                entry->ImageScore = entry->width * entry->height * depth;
                entry->x_hot = x_hot;
                entry->y_hot = y_hot;
                entry->DIBoffset = data_offset;