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use alpha channel in Blit() as well and not only in DrawBitmap()

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git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@20582 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Vadim Zeitlin
2003-05-11 11:14:35 +00:00
parent c9fcf5817f
commit 275a63e3a6
1 changed files with 106 additions and 67 deletions
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173
src/msw/dc.cpp
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@@ -117,11 +117,23 @@ static const int MM_METRIC = 10;
// convert degrees to radians // convert degrees to radians
static inline double DegToRad(double deg) { return (deg * M_PI) / 180.0; } static inline double DegToRad(double deg) { return (deg * M_PI) / 180.0; }
// call AlphaBlend() to blit contents of hdcSrc to hdcDst using alpha
//
// NB: bmpSrc is the bitmap selected in hdcSrc, it is not really needed
// to pass it to this function but as we already have it at the point
// of call anyhow we do
//
// return true if we could draw the bitmap in one way or the other, false
// otherwise
static bool AlphaBlt(HDC hdcDst,
int x, int y, int w, int h,
HDC hdcSrc,
const wxBitmap& bmpSrc);
#ifdef wxHAVE_RAW_BITMAP #ifdef wxHAVE_RAW_BITMAP
// our (limited) AlphaBlend() replacement // our (limited) AlphaBlend() replacement
static void static void
wxAlphaBlend(wxDC& dc, int x, int y, int w, int h, const wxBitmap& bmp); wxAlphaBlend(HDC hdcDst, int x, int y, int w, int h, const wxBitmap& bmp);
#endif #endif
// ---------------------------------------------------------------------------- // ----------------------------------------------------------------------------
@@ -957,72 +969,14 @@ void wxDC::DoDrawBitmap( const wxBitmap &bmp, wxCoord x, wxCoord y, bool useMask
HPALETTE oldPal = 0; HPALETTE oldPal = 0;
#endif // wxUSE_PALETTE #endif // wxUSE_PALETTE
// do we have AlphaBlend() and company in the headers?
#ifdef AC_SRC_OVER
if ( bmp.HasAlpha() ) if ( bmp.HasAlpha() )
{ {
// yes, now try to see if we have it during run-time MemoryHDC hdcMem;
SelectInHDC select(hdcMem, GetHbitmapOf(bmp));
typedef BOOL (WINAPI *AlphaBlend_t)(HDC,int,int,int,int, if ( AlphaBlt(GetHdc(), x, y, width, height, hdcMem, bmp) )
HDC,int,int,int,int, return;
BLENDFUNCTION);
// bitmaps can be drawn only from GUI thread so there is no need to
// protect this static variable from multiple threads
static bool s_triedToLoad = FALSE;
static AlphaBlend_t pfnAlphaBlend = NULL;
if ( !s_triedToLoad )
{
s_triedToLoad = TRUE;
// don't give errors about the DLL being unavailable, we're
// prepared to handle this
wxLogNull nolog;
wxDynamicLibrary dll(_T("msimg32.dll"));
if ( dll.IsLoaded() )
{
pfnAlphaBlend = (AlphaBlend_t)dll.GetSymbol(_T("AlphaBlend"));
if ( pfnAlphaBlend )
{
// we must keep the DLL loaded if we want to be able to
// call AlphaBlend() so just never unload it at all, not a
// big deal
dll.Detach();
}
}
}
if ( pfnAlphaBlend )
{
MemoryHDC hdcMem;
SelectInHDC select(hdcMem, GetHbitmapOf(bmp));
BLENDFUNCTION bf;
bf.BlendOp = AC_SRC_OVER;
bf.BlendFlags = 0;
bf.SourceConstantAlpha = 0xff;
bf.AlphaFormat = AC_SRC_ALPHA;
if ( pfnAlphaBlend(GetHdc(), x, y, width, height,
hdcMem, 0, 0, width, height,
bf) )
{
// skip wxAlphaBlend() call below
return;
}
wxLogLastError(_T("AlphaBlend"));
}
// use our own (probably much slower) implementation
#ifdef wxHAVE_RAW_BITMAP
wxAlphaBlend(*this, x, y, width, height, bmp);
#endif // wxHAVE_RAW_BITMAP
return;
} }
#endif // defined(AC_SRC_OVER)
if ( useMask ) if ( useMask )
{ {
@@ -1842,11 +1796,19 @@ bool wxDC::DoBlit(wxCoord xdest, wxCoord ydest,
int rop, bool useMask, int rop, bool useMask,
wxCoord xsrcMask, wxCoord ysrcMask) wxCoord xsrcMask, wxCoord ysrcMask)
{ {
wxCHECK_MSG( source, FALSE, _T("wxDC::Blit(): NULL wxDC pointer") );
#ifdef __WXMICROWIN__ #ifdef __WXMICROWIN__
if (!GetHDC()) return FALSE; if (!GetHDC()) return FALSE;
#endif #endif
const wxBitmap& bmpSrc = source->m_selectedBitmap; const wxBitmap& bmpSrc = source->m_selectedBitmap;
if ( bmpSrc.Ok() && bmpSrc.HasAlpha() )
{
if ( AlphaBlt(GetHdc(), xdest, ydest, width, height,
GetHdcOf(*source), bmpSrc) )
return TRUE;
}
wxMask *mask = NULL; wxMask *mask = NULL;
if ( useMask ) if ( useMask )
@@ -2306,19 +2268,96 @@ IMPLEMENT_DYNAMIC_CLASS(wxDCModule, wxModule)
#endif // wxUSE_DC_CACHEING #endif // wxUSE_DC_CACHEING
// ---------------------------------------------------------------------------- // ----------------------------------------------------------------------------
// wxAlphaBlend: our fallback if ::AlphaBlend() is unavailable // alpha channel support
// ---------------------------------------------------------------------------- // ----------------------------------------------------------------------------
static bool AlphaBlt(HDC hdcDst,
int x, int y, int width, int height,
HDC hdcSrc,
const wxBitmap& bmp)
{
wxASSERT_MSG( bmp.Ok() && bmp.HasAlpha(), _T("AlphaBlt(): invalid bitmap") );
wxASSERT_MSG( hdcDst && hdcSrc, _T("AlphaBlt(): invalid HDC") );
// do we have AlphaBlend() and company in the headers?
#ifdef AC_SRC_OVER
// yes, now try to see if we have it during run-time
typedef BOOL (WINAPI *AlphaBlend_t)(HDC,int,int,int,int,
HDC,int,int,int,int,
BLENDFUNCTION);
// bitmaps can be drawn only from GUI thread so there is no need to
// protect this static variable from multiple threads
static bool s_triedToLoad = FALSE;
static AlphaBlend_t pfnAlphaBlend = NULL;
if ( !s_triedToLoad )
{
s_triedToLoad = TRUE;
// don't give errors about the DLL being unavailable, we're
// prepared to handle this
wxLogNull nolog;
wxDynamicLibrary dll(_T("msimg32.dll"));
if ( dll.IsLoaded() )
{
pfnAlphaBlend = (AlphaBlend_t)dll.GetSymbol(_T("AlphaBlend"));
if ( pfnAlphaBlend )
{
// we must keep the DLL loaded if we want to be able to
// call AlphaBlend() so just never unload it at all, not a
// big deal
dll.Detach();
}
}
}
if ( pfnAlphaBlend )
{
BLENDFUNCTION bf;
bf.BlendOp = AC_SRC_OVER;
bf.BlendFlags = 0;
bf.SourceConstantAlpha = 0xff;
bf.AlphaFormat = AC_SRC_ALPHA;
if ( pfnAlphaBlend(hdcDst, x, y, width, height,
hdcSrc, 0, 0, width, height,
bf) )
{
// skip wxAlphaBlend() call below
return TRUE;
}
wxLogLastError(_T("AlphaBlend"));
}
#endif // defined(AC_SRC_OVER)
// AlphaBlend() unavailable of failed: use our own (probably much slower)
// implementation
#ifdef wxHAVE_RAW_BITMAP #ifdef wxHAVE_RAW_BITMAP
wxAlphaBlend(hdcDst, x, y, width, height, bmp);
return TRUE;
#else // !wxHAVE_RAW_BITMAP
// no wxAlphaBlend() neither, fall back to using simple BitBlt() (we lose
// alpha but at least something will be shown like this)
return FALSE;
#endif // wxHAVE_RAW_BITMAP
}
// wxAlphaBlend: our fallback if ::AlphaBlend() is unavailable
#ifdef wxHAVE_RAW_BITMAP
static void static void
wxAlphaBlend(wxDC& dc, int xDst, int yDst, int w, int h, const wxBitmap& bmpSrc) wxAlphaBlend(HDC hdcDst, int xDst, int yDst, int w, int h, const wxBitmap& bmpSrc)
{ {
// get the destination DC pixels // get the destination DC pixels
wxBitmap bmpDst(w, h, 32 /* force creating RGBA DIB */); wxBitmap bmpDst(w, h, 32 /* force creating RGBA DIB */);
MemoryHDC hdcMem; MemoryHDC hdcMem;
SelectInHDC select(hdcMem, GetHbitmapOf(bmpDst)); SelectInHDC select(hdcMem, GetHbitmapOf(bmpDst));
if ( !::BitBlt(hdcMem, 0, 0, w, h, GetHdcOf(dc), 0, 0, SRCCOPY) ) if ( !::BitBlt(hdcMem, 0, 0, w, h, hdcDst, 0, 0, SRCCOPY) )
{ {
wxLogLastError(_T("BitBlt")); wxLogLastError(_T("BitBlt"));
} }
@@ -2359,7 +2398,7 @@ wxAlphaBlend(wxDC& dc, int xDst, int yDst, int w, int h, const wxBitmap& bmpSrc)
} }
// and finally blit them back to the destination DC // and finally blit them back to the destination DC
if ( !::BitBlt(GetHdcOf(dc), xDst, yDst, w, h, hdcMem, 0, 0, SRCCOPY) ) if ( !::BitBlt(hdcDst, xDst, yDst, w, h, hdcMem, 0, 0, SRCCOPY) )
{ {
wxLogLastError(_T("BitBlt")); wxLogLastError(_T("BitBlt"));
} }