Amebis/wxWidgets
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

fixed CheckTransparency() for RGBA images

Browse Source 
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@20151 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Vadim Zeitlin
2003-04-12 00:03:16 +00:00
parent 7ce4426ae3
commit d26d975463
1 changed files with 35 additions and 22 deletions
Download Patch File Download Diff File Expand all files Collapse all files

57
src/common/imagpng.cpp
View File

@@ -189,14 +189,24 @@ PNGLINKAGEMODE wx_png_warning(png_structp png_ptr, png_const_charp message)
// LoadFile() helpers
// ----------------------------------------------------------------------------
// determine the kind of transparency we need for this image: if the only alpha
// values it has are 0 and 0xff then we can simply create a mask for it, we
// should be ok with a simple mask but otherwise we need a full blown alpha
// channel in wxImage
//
// parameters:
// ptr the start of the data to examine
// 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,
png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h)
png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h,
size_t numColBytes)
{
// suppose that a mask will suffice
Transparency transparency = Transparency_Mask;
// 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 char a2;
unsigned const char *ptr2 = ptr;
for ( png_uint_32 y2 = y; y2 < h; y2++ )
@@ -204,26 +214,19 @@ CheckTransparency(const unsigned char *ptr,
for ( png_uint_32 x2 = x + 1; x2 < w; x2++ )
{
// skip the grey byte
a2 = *++ptr2;
ptr2 += numColBytes;
a2 = *ptr2++;
if ( a2 && a2 != 0xff )
{
// not fully opeaque nor fully transparent, hence need alpha
transparency = Transparency_Alpha;
break;
// not fully opaque nor fully transparent, hence need alpha
return Transparency_Alpha;
}
++ptr2;
}
if ( transparency == Transparency_Alpha )
{
// no need to continue
break;
}
}
return transparency;
// mask will be enough
return Transparency_Mask;
}
unsigned char *InitAlpha(wxImage *image, png_uint_32 x, png_uint_32 y)
@@ -341,8 +344,13 @@ void CopyDataFromPNG(wxImage *image,
// maybe even full alpha channel info: the former is
// only enough if we have alpha values of 0 and 0xff
// only, otherwisewe need the latter
transparency = CheckTransparency(ptrSrc, x, y,
width, height);
transparency = CheckTransparency
(
ptrSrc,
x, y,
width, height,
1
);
if ( transparency == Transparency_Mask )
{
@@ -396,8 +404,13 @@ void CopyDataFromPNG(wxImage *image,
// where noted
if ( a != 0xff && transparency == Transparency_None )
{
transparency = CheckTransparency(ptrSrc, x, y,
width, height);
transparency = CheckTransparency
(
ptrSrc,
x, y,
width, height,
3
);
if ( transparency == Transparency_Mask )
{