'Bitmaps in WPF - give watermarking effect and then recover images individually
I am working on a project where I need to play with two bitmaps. I am putting them in a grid one over the other with reduced opacity (to give a watermark effect).
I am rendering the grid to a bitmap using RenderTargetBitmap and saving the bitmap to a file.
Now my requirement is to load the rendered bitmap again and recover the original pictures separately. Is there any way to recover the original images again. I am not able to think any algorithm to implement this.
My aim is to give a watermarking effect and then recover the images individually.
Solution 1:[1]
If your goal is to simulate watermarking and allow later 'dewatermarking', then assuming that you have your watermarking bitmap present at decoding time, you probably can do that. Sure you cannot use your initial approach - just simple merging of two layers is not reversible.
You need to use some reversible transformation, like rotating source image pixel RGB values vector, using watermark image pixel RGB values as parameters. While dewatermarking you just use negative values from watermark image.
Well, RGB vector is not ideal - you can go out of RGB space while rotating it. Probably you can find color space (or some other transformation in RGB space), better suited to your goal.
(English is not my first or even second language, thereby I apologize if you can't understand my idea - just ask over.)
Solution 2:[2]
No. The information is lost during "flattening" of the image.
You need to save both images and information about their properties (position, opacity) into single file. And restore it on load.
Solution 3:[3]
Why don't you try to make it two layers of bitmap?
Solution 4:[4]
i wonder if you can use TIFF format, where you can store multiple images. that way on display you can choose to show with/without watermark.
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | Arvo |
| Solution 2 | Euphoric |
| Solution 3 | Howard |
| Solution 4 | Bek Raupov |