Invert Colors

Posted By: Angus | Aug 2nd, 2005 @ 8:54 AM
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Comments: 9 | Views: 12054 | Downloads: 125
#Aug 2nd, 2005 @ 8:54 AM
Angus
Angus
.
Download:Link for Invert Colors(0 Bytes)
This program is one that inverts the colors of a picture. I was hoping that someone could tell me a way of making this program work faster, as currently it is somewhat lacking in speed.

Thanks in advance

Angus Higgins
#Aug 2nd, 2005 @ 11:17 AM
Yargnits
Yargnits
Instead of

                        int R = UserImage.GetPixel(WidthPixels, HeightPixels).R;
                        int G = UserImage.GetPixel(WidthPixels, HeightPixels).G;
                        int B = UserImage.GetPixel(WidthPixels, HeightPixels).B;
                        UserImage.SetPixel(WidthPixels, HeightPixels, Color.FromArgb(255 - R, 255 - G, 255 - B));

couldn't you do
                        int invert = 0xFFFFFF;
                        UserImage.SetPixel(WidthPixels, HeightPixels, Color.FromArgb(UserImage.GetPixel(WidthPixels, HeightPixels).ToArgb ^ invert);

(or some other more efficient way of XORing every pixel in the picture)?
#Aug 2nd, 2005 @ 12:05 PM
John Galt
John Galt
Use a ColorMatrix. It will be almost instant.
#Aug 2nd, 2005 @ 12:33 PM
Maurits
Maurits
AKA Matthew van Eerde
John Galt wrote:
Use a ColorMatrix. It will be almost instant.


ColorMatrix example from Bob Powell
Image img=Image.FromFile(<filename>);
Bitmap copy=new Bitmap(img.Width,img.Height);
ImageAttributes ia = new ImageAttributes();
ColorMatrix cm=new ColorMatrix();
cm.Matrix00=-1;
cm.Matrix11=-1;
cm.Matrix22=-1;
ia.SetColorMatrix(cm);
Graphics g=Graphics.FromImage(copy);
g.DrawImage(img,new Rectangle(0, 0, img.Width, img.Height), 0, 0, img.Width, img.Height, GraphicsUnit.Pixel, ia);
g.Dispose();
img.Dispose();
#Aug 3rd, 2005 @ 4:49 AM
Angus
Angus
.
I have made a program that uses ColorMatrix class, but it uses System.Drawing.Graphics, so it draws an image onto a component, is there a way to use System.Drawing.Graphics to draw onto a blank bitmap, or just implement the ColorMatrix class without System.Drawing.Graphics?

Thanks in advance

Angus Higgins
#Aug 3rd, 2005 @ 5:24 AM
Angus
Angus
.
Thanks for the tips you guys, I have finally made it go at a speed that is acceptable, I have updated the .zip file so you can have a look for yourself, the mostI have had to wait was about 1 second, and that was when I inverted a gargantuan image of dimensions 5120 by 1024 pixels, if you want to see it, it is here.

Thanks for all your help, I may extend the program to offer grayscale, and brightness changing.

Angus Higgins
#Aug 5th, 2005 @ 6:16 PM
Manip
Manip
Pretty interesting program I must say.
#Aug 6th, 2005 @ 11:29 AM
Angus
Angus
.
I have made one that does change in contrast, I'll put it up in a little while.

Angus Higgins

Change Brightness


[Save]
#Aug 8th, 2005 @ 10:00 PM
Loadsgood
Loadsgood
What is your answer?
Can anyone convert his app into a .NET 1.1 app? I'm too lazy to install .NET 2.0 and I'd love to be able to use it.



Make the Change Brightness program have its own thread.
Loadsgood.
#Aug 9th, 2005 @ 2:34 AM
Angus
Angus
.
Loadsgood wrote:
Make the Change Brightness program have its own thread.
Loadsgood.


OK, I'll add a new thread for change brightness.

Thanks

Angus Higgins
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