Alpha/Opacity change in image

Question

Hi,

We have a single class in my project which has a full screen image (800 * 480) .  We tried to change the opacity of the image from 50 to 100 for indefinite cycle with each cycle duration as 5000 ms.

We have placed the image/bitmap in RAM.

We tried to take time taken to update evry frame for this case. We observed like each frame update is taking 108 ms. Why it is taking this much time to update?

Best Regards,

Preethi S,

Robert Bosch - India

Answer 1

Hi Preethi,

the resulting performance may depend on the type of bitmap you are using.

For example, if you are using a NXP i.MX RT1050 hardware and you want to fade in / fade out a RGB565 bitmap, this can be done accellerated by the pixelpipeline (PXP). However, if you want to fade in / fade out a Index8 bitmap, this cannot be done by hardware - thus a software routine is doing the blend operation. Blending in software is always time consuming.

What kind of bitmaps (color format) are you using?

Best regards,

Manfred.

Comments

Hi Manfred,

Thanks for the quick reply.

When we use the bitmap format as RGBA8888 , frametime is 108 ms and if we try to use RGB565 bitmap format frametime is around 85 -90.

But we have not enabled PXP accelerator. We will try to enable the same and check the frametime.

Best Regards,

Preethi S.

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Additional remark: If you are using Platform Package with RGB565 color format, the PXP hardware is used. If you are using Platform Package with RGBA8888 color format, all blend operations have to be done by software.