LTDC_PIXEL_FORMAT_RGB888, framebuffer format?

[pk84]

Hello,

I'm using LTDC_Display_1Layer example.

In case I use "LTDC_PIXEL_FORMAT_RGB888" in which format should I store a picture in the framebuffer?

I did following, but the pictures is not displayed correctly. 24bit value of a pixel is stored in one 32bit array position. Is that wrong?

const uint32_t RGB888_1024x600[614400] =
 
{
 
	0x00ffffff, 0x00ffffff, 0x00ffffff, 0x00ffffff, 0x00ffffff, 0x00ffffff,
 
  0x00ffffff, 0x00ffffff, 0x00ffffff, 0x00ffffff, 0x00ffffff, 0x00ffffff,
 
 
 
..
 
  0x00ffffff, 0x00ffffff, 0x00ffffff, 0x00ffffff, 0x00ffffff, 0x00ffffff
 
};

[KnarfB]

RGB888 is, and has ever been, a 24-bit pixel format, not a 32-bit one. Either pack your pixels manually to 24-bit, say in a uint8_t array, or use LTDC_PIXEL_FORMAT_ARGB8888 which is a 32-bit format with a 4th alpha (blending) byte.

hth

KnarfB

[pk84]

Thank you. Still does not work with ARGB8888, at which position should be the 8bit alpha value?

Should it have the bold position, see below:

0x00ffffff

[pk84]

How must the pixels be arranged in the array?

At the moment it's simply first pixel up to last pixel...

[KnarfB]

#define LCD_COLOR_BLUE          ((uint32_t)0xFF0000FF)
#define LCD_COLOR_GREEN         ((uint32_t)0xFF00FF00)
#define LCD_COLOR_RED           ((uint32_t)0xFFFF0000)

[KnarfB]

Basically: yes, line by line. The lines in RAM may be longer than the actually visible part due to alignment. Depends on the setup. What board are you using?

hth

KnarfB

[pk84]

It's a custom board, see current display:

(layerCfg.WindowsX1 / Y1 set to 480 / 272 and layerCfg.Backcolor.Green = 255;)

[pk84]

Or does somebody know how can I generate from a picture (bmp, jpg, png) a LTDC_PIXEL_FORMAT_ARGB8888 compatible output/ C-File?

[KnarfB]

So the background works, but the pixels don't? Framebuffer in external RAM? Are you sure that the external RAM works correctly? Passed some RAM tests?

hth

KnarfB

[pk84]

I think is located at Flash memory (see screenshot below).... I use example from ST, "LTDC_Display_1Layer"

However, for testing purposes, how can I generate a RGB888 or ARGB8888 file from a picture?