87 lines
3.0 KiB
C
87 lines
3.0 KiB
C
// 16 august 2014
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#include "winapi_windows.h"
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#include "_cgo_export.h"
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HBITMAP unscaledBitmap(void *i, intptr_t dx, intptr_t dy)
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{
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BITMAPINFO bi;
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VOID *ppvBits;
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HBITMAP bitmap;
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ZeroMemory(&bi, sizeof (BITMAPINFO));
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bi.bmiHeader.biSize = sizeof (BITMAPINFOHEADER);
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bi.bmiHeader.biWidth = (LONG) dx;
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bi.bmiHeader.biHeight = -((LONG) dy); // negative height to force top-down drawing;
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bi.bmiHeader.biPlanes = 1;
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bi.bmiHeader.biBitCount = 32;
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bi.bmiHeader.biCompression = BI_RGB;
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bi.bmiHeader.biSizeImage = (DWORD) (dx * dy * 4);
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bitmap = CreateDIBSection(NULL, &bi, DIB_RGB_COLORS, &ppvBits, 0, 0);
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if (bitmap == NULL)
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xpanic("error creating HBITMAP for unscaled ImageList image copy", GetLastError());
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dotoARGB(i, (void *) ppvBits);
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return bitmap;
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}
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HIMAGELIST newImageList(int width, int height)
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{
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HIMAGELIST il;
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// TODO does this strip alpha?
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// sinni800 in irc.freenode.net/#go-nuts suggests our use of *image.RGBA makes this not so much of an issue
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il = (*fv_ImageList_Create)(width, height, ILC_COLOR32, 20, 20); // should be reasonable
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if (il == NULL)
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xpanic("error creating image list", GetLastError());
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return il;
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}
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void addImage(HIMAGELIST il, HBITMAP bitmap, int origwid, int oright, int width, int height)
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{
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BOOL wasScaled = FALSE;
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HDC scaledDC, origDC;
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HBITMAP scaled;
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HBITMAP prevscaled, prevorig;
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// first we need to scale the bitmap
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if (origwid == width && oright == height) {
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scaled = bitmap;
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goto noscale;
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}
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wasScaled = TRUE;
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scaledDC = GetDC(NULL);
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if (scaledDC == NULL)
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xpanic("error getting screen DC for scaled ImageList bitmap", GetLastError());
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scaled = CreateCompatibleBitmap(scaledDC, width, height);
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if (scaled == NULL)
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xpanic("error creating scaled ImageList bitmap", GetLastError());
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prevscaled = SelectObject(scaledDC, scaled);
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if (prevscaled == NULL)
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xpanic("error selecting scaled ImageList bitmap into screen DC", GetLastError());
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origDC = GetDC(NULL);
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if (origDC == NULL)
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xpanic("error getting screen DC for original ImageList bitmap", GetLastError());
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prevorig = SelectObject(origDC, bitmap);
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if (prevorig == NULL)
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xpanic("error selecting original ImageList bitmap into screen DC", GetLastError());
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if (StretchBlt(scaledDC, 0, 0, width, height,
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origDC, 0, 0, origwid, oright,
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SRCCOPY) == 0)
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xpanic("error scaling ImageList bitmap down", GetLastError());
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if (SelectObject(origDC, prevorig) != bitmap)
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xpanic("error selecting previous bitmap into original image's screen DC", GetLastError());
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if (DeleteDC(origDC) == 0)
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xpanic("error deleting original image's screen DC", GetLastError());
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if (SelectObject(scaledDC, prevscaled) != scaled)
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xpanic("error selecting previous bitmap into scaled image's screen DC", GetLastError());
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if (DeleteDC(scaledDC) == 0)
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xpanic("error deleting scaled image's screen DC", GetLastError());
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noscale:
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if ((*fv_ImageList_Add)(il, scaled, NULL) == -1)
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xpanic("error adding ImageList image to image list", GetLastError());
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if (wasScaled) // clean up
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if (DeleteObject(scaled) == 0)
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xpanic("error deleting scaled bitmap", GetLastError());
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}
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