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don't suppose that all 32bpp DIBs have alpha, this is not true, the extra byte may be just padding

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git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@28345 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Vadim Zeitlin
2004-07-20 23:45:28 +00:00
parent c1296b82d4
commit 45515b6685
2 changed files with 21 additions and 7 deletions
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6
include/wx/msw/dib.h
View File

@@ -194,6 +194,11 @@ private:
// the case // the case
bool m_ownsHandle; bool m_ownsHandle;
// if true, we have alpha, if false we don't (note that we can still have
// m_depth == 32 but the last component is then simply padding and not
// alpha)
bool m_hasAlpha;
// DIBs can't be copied // DIBs can't be copied
wxDIB(const wxDIB&); wxDIB(const wxDIB&);
@@ -209,6 +214,7 @@ void wxDIB::Init()
{ {
m_handle = 0; m_handle = 0;
m_ownsHandle = true; m_ownsHandle = true;
m_hasAlpha = false;
m_data = NULL; m_data = NULL;

22
src/msw/dib.cpp
View File

@@ -182,6 +182,8 @@ bool wxDIB::Create(const wxBitmap& bmp)
return false; return false;
} }
m_hasAlpha = bmp.HasAlpha();
return true; return true;
} }
@@ -634,8 +636,8 @@ bool wxDIB::Create(const wxImage& image)
// if we have alpha channel, we need to create a 32bpp RGBA DIB, otherwise // if we have alpha channel, we need to create a 32bpp RGBA DIB, otherwise
// a 24bpp RGB is sufficient // a 24bpp RGB is sufficient
const bool hasAlpha = image.HasAlpha(); m_hasAlpha = image.HasAlpha();
const int bpp = hasAlpha ? 32 : 24; const int bpp = m_hasAlpha ? 32 : 24;
if ( !Create(w, h, bpp) ) if ( !Create(w, h, bpp) )
return false; return false;
@@ -645,7 +647,8 @@ bool wxDIB::Create(const wxImage& image)
const int srcBytesPerLine = w * 3; const int srcBytesPerLine = w * 3;
const int dstBytesPerLine = GetLineSize(w, bpp); const int dstBytesPerLine = GetLineSize(w, bpp);
const unsigned char *src = image.GetData() + ((h - 1) * srcBytesPerLine); const unsigned char *src = image.GetData() + ((h - 1) * srcBytesPerLine);
const unsigned char *alpha = hasAlpha ? image.GetAlpha() + (h - 1)*w : NULL; const unsigned char *alpha = m_hasAlpha ? image.GetAlpha() + (h - 1)*w
: NULL;
unsigned char *dstLineStart = (unsigned char *)m_data; unsigned char *dstLineStart = (unsigned char *)m_data;
for ( int y = 0; y < h; y++ ) for ( int y = 0; y < h; y++ )
{ {
@@ -691,19 +694,20 @@ wxImage wxDIB::ConvertToImage() const
return wxNullImage; return wxNullImage;
} }
const int bpp = GetDepth(); if ( m_hasAlpha )
if ( bpp == 32 )
{ {
image.SetAlpha(); image.SetAlpha();
} }
// this is the same loop as in Create() just above but with copy direction // this is the same loop as in Create() just above but with copy direction
// reversed // reversed
const int bpp = GetDepth();
const int dstBytesPerLine = w * 3; const int dstBytesPerLine = w * 3;
const int srcBytesPerLine = GetLineSize(w, bpp); const int srcBytesPerLine = GetLineSize(w, bpp);
unsigned char *dst = image.GetData() + ((h - 1) * dstBytesPerLine); unsigned char *dst = image.GetData() + ((h - 1) * dstBytesPerLine);
unsigned char *alpha = image.HasAlpha() ? image.GetAlpha() + (h - 1)*w unsigned char *alpha = image.HasAlpha() ? image.GetAlpha() + (h - 1)*w
: NULL; : NULL;
const bool is32bit = bpp == 32;
const unsigned char *srcLineStart = (unsigned char *)GetData(); const unsigned char *srcLineStart = (unsigned char *)GetData();
for ( int y = 0; y < h; y++ ) for ( int y = 0; y < h; y++ )
{ {
@@ -717,8 +721,12 @@ wxImage wxDIB::ConvertToImage() const
dst += 3; dst += 3;
if ( alpha ) if ( is32bit )
*alpha++ = *src++; {
if ( alpha )
*alpha++ = *src;
src++;
}
} }
// pass to the previous line in the image // pass to the previous line in the image