Adding a Gif image with transparency

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Hi,
I am trying to add a gif image to a pdf file.
Perhaps my question is stupid, but is it possible to manage the transparency of that image if it is a gif file with transparency ?
I perform a AddImageFromFile, before a drawImage... and the result is an image with a white opaque backstyle... Do I do something wrong ?
Thanks in advance.
Eddy

Edited by Eddy - 18 Feb 09 at 12:58PM

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Eddy Members Profile Find Members Posts Beginner Joined: 17 Nov 08 Status: Offline Points: 16	Post Options Post Reply Quote Eddy Report Post Thanks(0) Quote Reply Topic: Adding a Gif image with transparency Posted: 18 Feb 09 at 12:57PM
	Hi, I am trying to add a gif image to a pdf file. Perhaps my question is stupid, but is it possible to manage the transparency of that image if it is a gif file with transparency ? I perform a AddImageFromFile, before a drawImage... and the result is an image with a white opaque backstyle... Do I do something wrong ? Thanks in advance. Eddy Edited by Eddy - 18 Feb 09 at 12:58PM

Autodidact Members Profile Find Members Posts Team Player Joined: 03 Feb 06 Status: Offline Points: 21	Post Options Post Reply Quote Autodidact Report Post Thanks(0) Quote Reply Posted: 18 Feb 09 at 2:05PM
	I have only tried placing PNG-files with transparency, and although the file format supports it, the result was just as you experience with the GIF-file. Since there are functions for making masks in the library, I tend to belive that transparence within the file is not supported. Check out the SetImageAsMask and SetImageMaskFromImage � and perhaps the ReverseImage. Maybe I should look into it myself too ... 8o)

Eddy Members Profile Find Members Posts Beginner Joined: 17 Nov 08 Status: Offline Points: 16	Post Options Post Reply Quote Eddy Report Post Thanks(0) Quote Reply Posted: 18 Feb 09 at 5:07PM
	In fact, I'm working on an application in whitch a user can create a pdf file and add images or text in it. So, I can't use the mask, since I don't know in advance whitch kind of image the user will add... I thought that quickpdf should manage that, may be I'm wrong... or maybe it is a pdf limitation... Thanks for your answer, even if it is not exactly what I was looking for... Eddy

Autodidact Members Profile Find Members Posts Team Player Joined: 03 Feb 06 Status: Offline Points: 21	Post Options Post Reply Quote Autodidact Report Post Thanks(0) Quote Reply Posted: 19 Feb 09 at 1:52AM
	You can set a mask based on colors in the image as well with SetImageMask/SetImageMaskCMYK, but then it is important that this color is not present in the part of the image that is to be preserved as it will make odd looking holes/gaps. In RGB, using pixels of 100% green should be the safest color to use. Using white would be asking for trouble, and as I see it, there are no way to specify a transparent pixel/color ... There is also SetClippingPath. Images can have a clipping path added in Photoshop. I assume that would be a bit much to ask from the user to create such a path, and I am not so sure this path is what the documentation refer to but rather a path created with the library. I assume so because the function have no argument to specify the path to use. It only uses the "current path" object. I guess this is a library limitation, where the creators maybe have chosen the easy route because the library has no support for EPS-vector graphics either, and I could really use that as EMF import is unstable, and neither it or WMF supports CMYK-colors.