fixed completely broken CheckForTransparency()

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@22249 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

diff --git a/src/common/imagpng.cpp b/src/common/imagpng.cpp
index bdbe0c5267e22894de8b155cf7bcd1a58c6ee0e7..66e917422ac619472ba14fdff90bba0a21471017 100644 (file)
--- a/src/common/imagpng.cpp
+++ b/src/common/imagpng.cpp
@@ -74,7 +74,7 @@ enum Transparency
 // return the kind of transparency needed for this image assuming that it does
 // have transparent pixels, i.e. either Transparency_Alpha or Transparency_Mask
 static Transparency
 // return the kind of transparency needed for this image assuming that it does
 // have transparent pixels, i.e. either Transparency_Alpha or Transparency_Mask
 static Transparency

-CheckTransparency(const unsigned char *ptr,
+CheckTransparency(unsigned char **lines,

                   png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h,
                   size_t numColBytes);
 
                   png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h,
                   size_t numColBytes);
 


@@ -210,13 +210,13 @@ PNGLINKAGEMODE wx_png_warning(png_structp png_ptr, png_const_charp message)
 // need a full blown alpha channel in wxImage
 //
 // parameters:
 // need a full blown alpha channel in wxImage
 //
 // parameters:

-//      ptr             the start of the data to examine
+//      lines           raw PNG data

 //      x, y            starting position
 //      w, h            size of the image
 //      numColBytes     number of colour bytes (1 for grey scale, 3 for RGB)
 //                      (NB: alpha always follows the colour bytes)
 Transparency
 //      x, y            starting position
 //      w, h            size of the image
 //      numColBytes     number of colour bytes (1 for grey scale, 3 for RGB)
 //                      (NB: alpha always follows the colour bytes)
 Transparency

-CheckTransparency(const unsigned char *ptr,
+CheckTransparency(unsigned char **lines,

                   png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h,
                   size_t numColBytes)
 {
                   png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h,
                   size_t numColBytes)
 {


@@ -225,15 +225,16 @@ CheckTransparency(const unsigned char *ptr,
 
     // suppose that a mask will suffice and check all the remaining alpha
     // values to see if it does
 
     // suppose that a mask will suffice and check all the remaining alpha
     // values to see if it does

-    unsigned const char *ptr2 = ptr;
-    for ( png_uint_32 y2 = y; y2 < h; y2++ )
+    for ( ; y < h; y++ )

     {
     {

+        unsigned const char *ptr = lines[y] + x;
+

         for ( png_uint_32 x2 = x; x2 < w; x2++ )
         {
             // skip the grey or colour byte(s)
         for ( png_uint_32 x2 = x; x2 < w; x2++ )
         {
             // skip the grey or colour byte(s)

-            ptr2 += numColBytes;
+            ptr += numColBytes;

 
 

-            unsigned char a2 = *ptr2++;
+            unsigned char a2 = *ptr++;

 
             if ( !IsTransparent(a2) && !IsOpaque(a2) )
             {
 
             if ( !IsTransparent(a2) && !IsOpaque(a2) )
             {


@@ -365,7 +366,7 @@ void CopyDataFromPNG(wxImage *image,
                     // only, otherwisewe need the latter
                     transparency = CheckTransparency
                                    (
                     // only, otherwisewe need the latter
                     transparency = CheckTransparency
                                    (

-                                        ptrSrc,
+                                        lines,

                                         x, y,
                                         width, height,
                                         1
                                         x, y,
                                         width, height,
                                         1


@@ -437,7 +438,7 @@ void CopyDataFromPNG(wxImage *image,
                 {
                     transparency = CheckTransparency
                                    (
                 {
                     transparency = CheckTransparency
                                    (

-                                        ptrSrc,
+                                        lines,

                                         x, y,
                                         width, height,
                                         3
                                         x, y,
                                         width, height,
                                         3