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DrawWin32.cpp: PrintDraw::InitPrinter() [message #19187]

Tue, 18 November 2008 16:09

Tom1
Messages: 1303
Registered: March 2007

Ultimate Contributor

Hi,

May I (?) suggest changing the code for DrawWin32.cpp: PrintDraw::InitPrinter() as follows:

Current:

::SetMapMode(handle, MM_ANISOTROPIC);
::SetViewportExtEx(handle, inchPixels.cx, inchPixels.cy, NULL);
::SetViewportOrgEx(handle, 0, 0, NULL);
::SetWindowExtEx(handle, 600, 600 , NULL);
::SetWindowOrgEx(handle, 0, 0, NULL);

Modified:

::SetMapMode(handle, MM_ANISOTROPIC);
::SetWindowExtEx(handle,pagePixels.cx,inchPixels.cx*pagePixels.cy/inchPixels.cy,NULL);
::SetWindowOrgEx(handle, 0, 0, NULL);
::SetViewportExtEx(handle, pagePixels.cx, pagePixels.cy, NULL); 
::SetViewportOrgEx(handle, 0, 0, NULL);
pagePixels.cy=inchPixels.cx*pagePixels.cy/inchPixels.cy;

I ended up changing this because I faced multiple problems while printing on an Epson Stylus Photo 1290. The raster and vector coordinate spaces were different since the printer's native 360x360 or 720x720 dpi resolution did not nicely map to the default 600x600 dpi resolution. Also, when printing large images, the image was trashed for some reason. (I made a custom ::SetDIBitsToDevice() based "DrawImage" replacement to circumvent that, but that's another story.)

The modification attempts to present a device context with native pixels, if possible, and also tries to adjust non-square device pixels to square device context pixels.

Also, the Draw::GetPagePixels now returns the corrected value. (This was not the case before and it was a part of the problem.)

NOTE: If somebody has a printer (device context) with non-square pixels, it would be good to test if this change breaks anything on printing of vectors and/or rasters. (The Epson's printer pixel is not square, but the device context pixel from the printer driver is luckily square.)

If someone really relies on the fixed 600x600 dpi resolution of a upp generic printer device, they may possibly not like my suggestion.

// Tom

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