CODEWITHSUNDEEP
c#graphics
James
James

Reputation: 1852

Finding the background colour System.Drawing.Bitmap

After I've drawn an object in the bitmap, I'd like to move it, so I need to draw the object again in the background colour, before drawing again in the proper colour. Assuming this is the correct approach, how do I find out what the background colour actually is? Thanks, James

Upvotes: 0

Views: 323

Answers (2)

saamorim
saamorim

Reputation: 3905

Since you have control on the canvas and if you have a "clean" canvas, you can get the color of any pixel before drawing and that should be your background color.

But remember, you don't have a background color on a regular bitmap, just a bunch of pixels! So if your canvas is not clear, or if you don't have a way to get the color before drawing, you have to make assumptions. There a quite a few solutions depending on your requirements. My suggestions are:

  • You can assume the pixel on the corner are your background colors
  • The color that appears more often is the background color

Upvotes: 1

user1314926
user1314926

Reputation: 180

Once you draw your object you can only use GetPixel to obtain the colour:

Bitmap.GetPixel(x,y)

Why not just clearing the whole bitmap and rewriting your object again? If your bitmap is not extremely large, you won't probably even notice any difference in performance.

Upvotes: 1

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