Semi transparent images when rendered on canvas looks darker than original image.

[maruthichilamakuri]

Semi transparent images looks darker when drawn on SKCanvasView than the original image.
It looks like the pixels are premultiplied twice.

Is it an issue or not with skia?

[identity-wael]

Double premultiplication is one possible cause, but the symptom alone isn't enough to identify a Skia bug. The key is how the image reaches DrawImage/DrawBitmap: decoded PNG, raw pixel buffer, or an intermediate render target?

For an 8-bit red pixel at roughly 50% opacity, the representations are:

• Straight/unpremultiplied RGBA: (255, 0, 0, 128).
• Premultiplied RGBA: (128, 0, 0, 128).

If a buffer containing the second representation is declared Unpremul, the renderer can multiply it again, producing the dark result you describe. The pixel bytes and SKImageInfo.AlphaType must agree; changing the label alone doesn't convert the bytes. See SKAlphaType.

A useful minimal comparison is to decode the original file directly with SkiaSharp and draw it once onto an explicitly opaque white canvas, with no paint opacity/filter or intermediate bitmap. Compare that to your current loading/conversion path on the same white background. If only the latter is dark, investigate its raw-pixel alpha declaration/conversion first. If direct decoding also differs, include the original image, SkiaSharp version/platform and the drawing code; color-space handling and the comparison application's background can also affect the result.

[maruthichilamakuri]

If SKCanvasView is replaced with SKGLView then the image is rendered as expected. Hence, wondering it could be double premultiplication.