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fixes for reading bitmapswith BI_BITFIELDS (patch 597906)

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git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@17023 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Vadim Zeitlin 2002-09-06 18:00:32 +00:00
parent 42ba812b70
commit 9042a01738
1 changed files with 28 additions and 7 deletions
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35
src/common/imagbmp.cpp
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@ -450,6 +450,7 @@ bool wxBMPHandler::DoLoadDib(wxImage * image, int width, int height,
{
wxInt32 aDword, rmask = 0, gmask = 0, bmask = 0;
int rshift = 0, gshift = 0, bshift = 0;
int rbits = 0, gbits = 0, bbits = 0;
wxInt32 dbuf[4];
wxInt8 bbuf[4];
wxUint8 aByte;
@ -529,11 +530,11 @@ bool wxBMPHandler::DoLoadDib(wxImage * image, int width, int height,
{
int bit = 0;
stream.Read(dbuf, 4 * 3);
bmask = wxINT32_SWAP_ON_BE(dbuf[0]);
rmask = wxINT32_SWAP_ON_BE(dbuf[0]);
gmask = wxINT32_SWAP_ON_BE(dbuf[1]);
rmask = wxINT32_SWAP_ON_BE(dbuf[2]);
// find shift amount.. ugly, but i can't think of a better way:
for (bit = 0; bit < bpp; bit++)
bmask = wxINT32_SWAP_ON_BE(dbuf[2]);
// find shift amount (Least significant bit of mask)
for (bit = bpp-1; bit>=0; bit--)
{
if (bmask & (1 << bit))
bshift = bit;
@ -542,6 +543,16 @@ bool wxBMPHandler::DoLoadDib(wxImage * image, int width, int height,
if (rmask & (1 << bit))
rshift = bit;
}
// Find number of bits in mask (MSB-LSB+1)
for (bit = 0; bit < bpp; bit++)
{
if (bmask & (1 << bit))
bbits = bit-bshift+1;
if (gmask & (1 << bit))
gbits = bit-gshift+1;
if (rmask & (1 << bit))
rbits = bit-rshift+1;
}
}
else if ( bpp == 16 )
{
@ -551,6 +562,9 @@ bool wxBMPHandler::DoLoadDib(wxImage * image, int width, int height,
rshift = 10;
gshift = 5;
bshift = 0;
rbits = 5;
gbits = 5;
bbits = 5;
}
else if ( bpp == 32 )
{
@ -560,6 +574,9 @@ bool wxBMPHandler::DoLoadDib(wxImage * image, int width, int height,
rshift = 16;
gshift = 8;
bshift = 0;
rbits = 8;
gbits = 8;
bbits = 8;
}
}
@ -714,11 +731,15 @@ bool wxBMPHandler::DoLoadDib(wxImage * image, int width, int height,
stream.Read(&aWord, 2);
aWord = wxUINT16_SWAP_ON_BE(aWord);
linepos += 2;
temp = (aWord & rmask) >> rshift;
/* use the masks and calculated amonut of shift
to retrieve the color data out of the word. Then
shift it left by (8 - number of bits) such that
the image has the proper dynamic range */
temp = (aWord & rmask) >> rshift << (8-rbits);
ptr[poffset] = temp;
temp = (aWord & gmask) >> gshift;
temp = (aWord & gmask) >> gshift << (8-gbits);
ptr[poffset + 1] = temp;
temp = (aWord & bmask) >> bshift;
temp = (aWord & bmask) >> bshift << (8-bbits);
ptr[poffset + 2] = temp;
column++;
}