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#1 Posted : Monday, June 20, 2005 2:38:08 AM(UTC)

Groups: Registered
Posts: 2

I was trying to print to a postscript color printer. Creating a device context and painting a bitmap generates a black and white output.


Investigating the Device Caps I see Differences:
BITSPERPIXEL: Postscript-Driver: 1, Other: 24
NUMCOLORS: Postscript-Driver: 8, Other: 16384


=> L_PaintDC dithers the output to black and white.


Is there a way to paint a bitmap in color to a device context with BITSPERPIXEL = 1? How is it possible to print to a postscript driver in color?


With Microsoft Word I can print a color bitmap.


From the Adobe Forum I get the answer that they know the problem, but they (or Microsoft) will not change the postscript drivers.


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#2 Posted : Tuesday, June 21, 2005 3:08:18 AM(UTC)


Groups: Registered, Tech Support
Posts: 20

Article 58LHQ in the FAQ section of our support site explains this.
I'm copying it here:

Why does my color Post Script printer only print black and white when I print a color image with LEADTOOLS?
Most PostScript printer drivers return a value of 1 for BITSPIXEL and 1 for PLANES in calls to the Windows function GetDeviceCaps for the DC. One can calculate device bits per pixel as BITSPIXEL * PLANES and the result should be 1 for an EPS printer. This results in 1-bit printing, as our paint function will try to pre-process the image to match the driver.

The workaround is to call the L_SetDisplayMode (DLL) function and turn off the Dither Paint and Index paint for a color EPS printer. You should reset the display mode after painting to the printer DC in order for LEAD to properly paint images to your display DC.


L_UINT32 uiOldFlags;

//Before printing
//Do your printing


Amin Dodin
LEADTOOLS Technical Support

#3 Posted : Tuesday, June 21, 2005 4:14:31 AM(UTC)

Groups: Registered
Posts: 2

Thanks a lot. It works.

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