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Ayke van Laethem
f6d399ec08
The existing code was broken in a few ways:
- It didn't use the correct operator precedence for the VSCRDEF VSA
variable: it needed some extra parentheses to be correct.
- It used the configured height instead of the actual display height
for calculating VSA, which is incorrect. TFA+VSA+BFA must always be
exactly 320, even if a lower value is configured.
- If a lower than 320 pixel height is configured, the bottomFixedArea
parameter applied to the whole 320 pixel screen height. Because this
seems counter intuitive (and relies on properties of any given
screen), I've changed it to work from the actual visible bottom of
the screen (which may be smaller than 320 pixels).
TODO: this doesn't take RowOffset into account, while it probably
should.
I haven't fixed the st7735 implementation, because I didn't have example
code on hand that would easily work on a st7735 screen. This is left as
a TODO for the future.
ST7735 driver
There are multiple devices using the ST7735 chip, and there are multiple versions ST7735B, ST7735R & ST7735S. Two apparently identical displays might have different configurations. The most common issues are:
- Colors are inverted (black is white and viceversa), invert the colors with display.InvertColors(true)
- Colors are not right (red is blue and viceversa, but green is ok), some displays uses BRG instead of RGB for defining colors, change the mode with display.IsBGR(true)
- There is noise/snow/confetti in the screen, probably rows and columns offsets are wrong, configure them with st7735.Config{RowOffset:XX, ColumnOffset:YY}
If nothing of the above works, your device may need a different boot-up process.