CODEWITHSUNDEEP
c#imageimage-processingresize
Tom Esterez
Tom Esterez

Reputation: 22157

Image border missing after downscaling

When I resize a bitmap using Graphics class, it seams that some right and bottom pixels of the original image are omited.

Here is an example (original, 60x60, 30x30):

original result60 result30

my code:

foreach(int x in new[]{60, 30})
{
    var result = new Bitmap(x, x);
    var g = Graphics.FromImage(result);
    g.DrawImage(new Bitmap(MediaDir + "original.png"), 0, 0, x, x);
    result.Save(MediaDir + "result" + x + ".png", ImageFormat.Png);
}

Am I missing something ?

edit, here is the result using HighQualityBicubic:

enter image description here enter image description here enter image description here enter image description here

Upvotes: 3

Views: 225

Answers (3)

Csharpnewbie
Csharpnewbie

Reputation: 1

i used this workaround fot that "bug". When i resized standart eshop item photo, some have gray left/top border and some not. So u just use this code

g.DrawImage(src, -1, -1, width+1, height+1);

and its work perfectly. I also find some hints about pixelmode or try use some special attr with drawimage method but it doesnt work for me.

Upvotes: 0

ZombieSheep
ZombieSheep

Reputation: 29963

It is likely to be an effect of the resizing process itself. Depending on the algorithm used, it may be detecting the red colour of the pixels at the border as being no longer as relevant to the overall image as the white ones, so the white on is output.

Upvotes: 2

Mark Ransom
Mark Ransom

Reputation: 308462

Set the interpolation mode to InterpolationMode.HighQualityBicubic.

You can see the effects of the parameter in a Microsoft Tutorial. The bottom left example has similar problems to yours.

Upvotes: 3

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