Fix edge detection and reenable entropy crop tests #1145
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Codecov Report
@@ Coverage Diff @@
## master #1145 +/- ##
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+ Coverage 82.27% 82.29% +0.01%
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Files 679 680 +1
Lines 29274 29301 +27
Branches 3278 3279 +1
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+ Hits 24085 24112 +27
Misses 4500 4500
Partials 689 689
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I tried to follow the discussions under #1143, but maybe missed a few points. What is the main reason you've chosen this vs premultiplication? I wonder how does OpenCV or ImageMagic work for images with alpha. @dlemstra do you know or can you quickly check it? |
| PixelOperations<TPixel>.Instance.ToVector4(this.configuration, targetRowSpan.Slice(0, span.Length), span, PixelConversionModifiers.Scale); | ||
| ref Vector4 baseRef = ref MemoryMarshal.GetReference(span); | ||
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| for (int x = 0; x < this.bounds.Width; x++) | ||
| { | ||
| ref Vector4 v = ref Unsafe.Add(ref baseRef, x); | ||
| v.W = 1F; | ||
| } | ||
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| PixelOperations<TPixel>.Instance.FromVector4Destructive(this.configuration, span, targetRowSpan, PixelConversionModifiers.Scale); |
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Yet another place where an extended PixelTypeInfo would be super useful to eliminate unnecessary scanning. Related discussion.
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@antonfirsov We do use premultiplication but then reassign the alpha value from the source before unpremultiplying. If you don't do that you end up with a blank image if you have a consistent alpha channel. Basically the only thing I changed was to normalize the alpha component before the algorithm runs. OpenCV does the same. In the link you can see it's picking up changes that would not exist without removing the alpha component first. PIL doesn't do this and will produce an entirely transparent image. (However in that closed issue they've misidentified the result as having a zero alpha channel, when, in fact, the image has no information in any channels. |
antonfirsov
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Small naming suggestion, otherwise LGTM.
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| namespace SixLabors.ImageSharp.Processing.Processors.Filters | ||
| { | ||
| internal sealed class OpaqueProcessor<TPixel> : ImageProcessor<TPixel> |
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Wouldn't be MakeOpaqueProcessor better? (Related extension to be added later: image.MakeOpaque().)
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We can do that if/when we choose to expose such an extension.
Prerequisites
Description
Edge detection now produces fully opaque output. This stabilizes the output across platforms and also fixes entropy cropping.