In the prototyping environment ,how to support multi-frame images using ExternBitmap

Question

Hi All,

I saw that the ExternBitmapLoader.ewi of ExternBitmap has been implemented in https://doc.embedded-wizard.de/using-extern-bitmap?v=9.30. 

so I directly copied the ExternBitmapLoader.ewi file in the using-extern-bitmap-1 project to my project. There were two problems when I was running in the prototyping:
1. In Bitmap, I can switch between different frames by changing the FrameNumber attribute, but in ExternBitmap, it seems that this cannot be done, and the Framesize attribute is read-only and cannot be assigned.
2. When I changed the PlatformPackage in the project from Tara.Win32.RGBA888 to Tara.Generic_OpenGL.RGBA8888, the color of all pictures changed, It seems that ExternBitmapLoader.ewi only supports Tara.Win32.RGBA888 without considering Tara.Generic_OpenGL.RGBA8888 color conversion.

Looking forward to your answer， thanks.

Answer 1

Hello,

the referenced ExternBitmapLoader.ewi is an example of how to integrate an external image decoder. This example limits to single-frame bitmaps only. Similarly, the module is compiled with color format valid for Win32 RGBA8888 target system. Other platforms (e.g. OpenGL) may have other layout of how pixel are stored. This may lead to the observed wrong colors being shown during the Prototyping.

In the practice, you should implement your own intrinsic module by taking in account your particular needs (e.g. support for multi-frame bitmaps) as well as the correct color format of the pixel stored in the bitmap. See following sections:

Multi-frame and animated bitmaps (explains the implementation aspects for multi-frame bitmaps)

Take in account the color format of the bitmap (Addresses the different color formats)

Implementing Prototyper intrinsics (Explains how you implement your own intrinsic modules)

LibPNG for NXP with FatFS (ASK thread treating similar question of how to use multi-frame extern bitmaps)

I hope it helps you further.

Best regards

Paul Banach