2014.02.04 23:29 "[Tiff] LibTiffDelphi and 1bit tiff", by Martin Masci

2014.02.04 23:41 "Re: [Tiff] LibTiffDelphi and 1bit tiff", by Bob Friesenhahn

On Wed, 5 Feb 2014, Martin Masci wrote:

> Hi,

> I'm using LibTiffDelphi to convert a bitmap image to 1bit tiff image. > This is my code:

Now I need control threshold to change contrast. In FreeImage for example I can use function to  Threshold(Value) change from 0 to 255 value.  threshold

> How can I edit threshold with LibTiffDelphi?

An operation like thresholding would require values spanning a range (e.g. 0-255) but this program only seems to accept input data with one bit per pixel (a true bitmap).

If you were to write a colormapped output image instead then you could use the colormap to cause the one bit of data to be displayed with a particular color or particular shade of gray. This is not the same as thresholding but can emulate contrast if all you need to do is lessen the displayed contrast rather than do actual value thresholding.

Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/