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restored (and slightly improved) wxImage::Scale() fix

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git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@10579 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Vadim Zeitlin
2001-06-15 01:30:21 +00:00
parent 4f53efae0f
commit 6721fc3852
1 changed files with 27 additions and 11 deletions
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38
src/common/image.cpp
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@@ -210,7 +210,14 @@ wxImage wxImage::Scale( int width, int height ) const
wxCHECK_MSG( Ok(), image, wxT("invalid image") ); wxCHECK_MSG( Ok(), image, wxT("invalid image") );
wxCHECK_MSG( (width > 0) && (height > 0), image, wxT("invalid image size") ); // can't scale to/from 0 size
wxCHECK_MSG( (width > 0) && (height > 0), image,
wxT("invalid new image size") );
long old_height = M_IMGDATA->m_height,
old_width = M_IMGDATA->m_width;
wxCHECK_MSG( (old_height > 0) && (old_width > 0), image,
wxT("invalid old image size") );
image.Create( width, height ); image.Create( width, height );
@@ -219,23 +226,32 @@ wxImage wxImage::Scale( int width, int height ) const
wxCHECK_MSG( data, image, wxT("unable to create image") ); wxCHECK_MSG( data, image, wxT("unable to create image") );
if (M_IMGDATA->m_hasMask) if (M_IMGDATA->m_hasMask)
image.SetMaskColour( M_IMGDATA->m_maskRed, M_IMGDATA->m_maskGreen, M_IMGDATA->m_maskBlue ); {
image.SetMaskColour( M_IMGDATA->m_maskRed,
long old_height = M_IMGDATA->m_height; M_IMGDATA->m_maskGreen,
long old_width = M_IMGDATA->m_width; M_IMGDATA->m_maskBlue );
}
char unsigned *source_data = M_IMGDATA->m_data; char unsigned *source_data = M_IMGDATA->m_data;
char unsigned *target_data = data; char unsigned *target_data = data;
for (long j = 0; j < height; j++) // We do (x, y) -> (x, y)*oldSize/newSize but the valid values of x and y
// are from 0 to size-1, hence all decrement the sizes
long old_old_width = old_width;
old_height--;
old_width--;
height--;
width--;
for ( long j = 0; j <= height; j++ )
{ {
long y_offset = (j * old_height / height) * old_width; // don't crash for images with height == 1
long y_offset = height ? (j * old_height / height)* old_old_width : 0;
for (long i = 0; i < width; i++) for ( long i = 0; i <= width; i++ )
{ {
memcpy( target_data, long x_offset = width ? (i * old_width) / width : 0;
source_data + 3*(y_offset + ((i * old_width )/ width)),
3 ); memcpy( target_data, source_data + 3*(y_offset + x_offset), 3 );
target_data += 3; target_data += 3;
} }
} }