Clarifications regarding PALETTED8 format
Hello,
I was reading through the forum and the FT81X Series Programmer's Guide for any clues regarding the PALETTED8 format. The forum has this 2018 thread:
https://support.newhavendisplay.com/hc/en-us/community/posts/10814396709527-EVE2-Palette8-Pixels
but I don't think it arrived at any resolution.
Figure 9 within with programmer's guide provides the PALETTED8 pixel format, which is basically (using SystemVerilog concatenation)
pixel[31:0] = { alpha[7:0], red[7:0], green[7:0], blue[7:0] };
That pixel format seems pretty straightforward (just 4 bytes per pixel). However, Code Snippet 10 (on the following page in the PDF) mentions something else -- a palette lookup table.
// addr_pal is the starting address of the palette lookup table in RAM_G
The example code proceeds to use addr_pal, as though it is distinct from the bitmap source, which gets specified as BITMAP_SOURCE(0).
So, some questions:
- What is the palette lookup table? Is it distinct from the pixel data for the bitmap? In other words, should addr_pal just be 0 in Code Snippet 10?
- If one just has a 24-bit true color image, can one just omit the drawing of the Alpha channel? Could the all-zero bytes also just be omitted, such that each pixel just occupies 3 bytes in RAM_G memory, or is the 4-byte per pixel implicit with PALETTED8?
Thanks,
Matt
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Hi Matt,
Unfortunately your question is above the scope of our software knowledge.
FTDI may assist you more expertly in this topic. Please submit an email request to them for their support on this question.
http://www.ftdichip.com/FTContact.htm.
Best Regards,0
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