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Topic: Arduino Mega project with ST7735 TFT 1.44 - adafruit vs PDQ  (Read 40 times) previous topic - next topic


I am creating a project where I am trying to write to dual ST7735 TFT 1.44 displays (arduino mega)

I have tried using the adafruit library tft.drawBitmap() function and have successfully got it drawing on both screens simultaneously. However I am finding the performance slower than what I require.

After googling, I came across the PDQ library, which I have got working successfully and the performance appears to be significantly better. However I can only get it working on 1 screen. It doesnt appear to support  2 screens?

So my questions are:

1) Is there a way to get PDQ working on 2+ screens ? 
2) If not, is there a way to improve the performance of the adafruit library ? I am writing single color bitmaps in progmem, but need to achieve smooth scrolling.


Seriously.   Two 128x128 screens could be replaced by a single 320x240 screen.
And you can even fit two 128x160 screens.

Adafruit's drawBitmap() family just uses Adafruit_GFX with individual drawPixel() calls.

Adafruit's SPITFT class (e.g. ST7735, ST7789, ILI9341, ...) optimises the drawRGBBitmap() method for this hardware.

So if you write your own drawMonoBitmap() function it can render it very fast via  tft.drawRGBBitmap()

This will give you fast mono pictures for little effort with Adafruit hardware SPI libraries.

Much easier than attempting to alter PDQ_xxx family for multiple screens.
Of course you could just use a single PDQ_ILI9341 screen with zero effort.


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