Strange scaling when using ICAP_UNITS, TWUN_PIXELS

[Anonymous]

I am writing a twain app using a HP 4890 scanner.
When I set it up with CAP_UNITS, TWUN_PIXELS and
requests an image of 200 x 100 pix I get 132 x 67 pix.
Iow. 2/3 of the requested dimensions.
I can correct this by setting X and Y scaling to 1.5.
Same result i native and memory transfer.
I assume this is a bug in the scanner DS, or do
you know any other possible cause of this.

regards
Rehn

[hpb]

Yes, this is a bug in the source code. When the client sets image layout in pixels, the size is interpreted by the source as if the resolution is fixed 300ppi, which predictably results in an incorrect scan size for all resolutions other than 300.
Workaround — use 300ppi or set the size in inches or cm.

[Author]

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