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Hello,

In our GUI we are using an RGBA8888 gradient bitmap resource with Platform package RGB565. The bitmap format is Native, so as expected there is a color loss/distortion observed in gradient due to conversion from RGBA8888 to the native format which is RGB565. In order to improve the quality of the bitmap, we tried to use the attribute Dithering. In-spite of using the option and trying with all the given dithering algorithms, there is no difference in the color loss/appearance of the gradient bitmap. Can you please suggest a solution to this?

Regards,

Kavya.

1 Answer

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by

Hello Kavya,

your observation is correct. The attribute Dithering has an effect only when color reduction is applied between the original image data and the desired target color format. Since the bitmap is configured RGBA8888 (Native in your Platform Package), there is no color reduction. It is already the maximum possibly color space.

Does the image contain any transparency or semi transparent colors? If not, I would recommend to configure the bitmap resource with the format RGB565. Then test the different Dithering modes.

Alternative approach: use an external graphic editor to enforce a color reduction in the original image file. Possibly such editor may also add additional dithering during this operation.

I hope it helps you further.

Best regards

Paul Banach

by

Hello Paul,

In our use case, color reduction should be applied between original image(RGBA8888) and desired color format(RGB565). Here, the Platform package is RGB565, so on configuring Native(internally, the native bitmaps are stored in the color format corresponding to the selected platform package - RGB565 in our case), we expect color reduction from RGBA8888 to RGB565 when a dithering algorithm is applied.

Using an external editor to add dithering works, but we want to know the significance of this attribute Dithering in such use cases.

Regards,

Kavya

by

Hello Kavya,

I think, it is a misunderstanding. RGB565 refers to the frame buffer format. The Native format (as bitmap format) is in this case still RGBA8888. See also Supported Frame Buffer and Bitmap Formats. From technical point of view, Native format has to support opacity + color information. RGB565 does not support opacity. In this case the next higher format RGBA8888 is the Native format.

As explained in my answer above, you can configure the the bitmap to be stored in RGB565 format. Then dithering will be applied. Note, that such RGB565 bitmap will not support any opacity information.

Best regards

Paul Banach

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