RA8875 and 5.0" 40 Pin TFT Display Overlap Pixels

Other Hardware Displays
1

I'm using the RA8875 display driver board and a 5.0" 800x480 TFT LCD display from Adafruit. Using an Arduino Due and interfacing with the display using SPI.

I'm trying to generate a heat map of sorts on the LCD using X and Y data points that correlate to a pixel/region of screen and an analog input that correlates to a certain color.

As I have the code right now - I am using the fillRoundRect command to fill an area of the screen with a color but if the Due recieves the same X/Y data or close to it - I will get overlapping rectangles or just covering up of the previous rectangle.

I tried to resolve this by declaring previousX and previousY variables but it didn't work. See below/attached for the code displaying the data.

Is there a way to instruct the LCD/RA8875 to not overwrite pixels that it has already colored in/displayed something on?

Once a portion of the screen has been filled in - I want it to be permanent.

Any help you can provide is greatly appreciated. Thank you

void DisplayData() {

screenX = Xaverage * Xratio;
screenY = 480 - (Yaverage * Yratio);

if (y >= 0 && screenY < 480 && x >= 0 && screenX <= 800) {

if (previousX != screenX && previousY != screenY) {

previousX = screenX;
previousY = screenY;

if (average > 2000) {
tft.fillRoundRect(screenX, screenY, 20, 20, 5, RA8875_WHITE);
}
if (1900 < average && average <= 2000) {
tft.fillRoundRect(screenX, screenY, 20, 20, 5, RA8875_YELLOW);
}
if (1600 < average && average <= 1900 ) {
tft.fillRoundRect(screenX, screenY, 20, 20, 5, RA8875_ORANGE);
}
if (1200 < average && average <= 1600) {
tft.fillRoundRect(screenX, screenY, 20, 20, 5, RA8875_RED);
}
if (900 < average && average <= 1200) {
tft.fillRoundRect(screenX, screenY, 20, 20, 5, RA8875_PURPLE);
}
if (200 < average && average <= 900) {
tft.fillRoundRect(screenX, screenY, 20, 20, 5, RA8875_NAVY);
}
if (average <= 200) {
tft.fillRoundRect(screenX, screenY, 20, 20, 5, RA8875_BLACK);
}
}
}
}

DisplayData.ino (1.13 KB)

2

You will have to calculate any overlap. And draw any uneven shapes by hand.

Or simply draw in the correct order.

David.

3

The X and Y data points are not something I know beforehand. They are generated based on position so I don't think I can calculate the overlap in data points - it's different everytime. Can you elaborate on any of your suggestions. Thanks,

Kyle

4

Take a piece of paper and a handful of flourescent marker pens.

I am not familiar with Adafruit_RA8875. You can colour fill an irregular shape by reading the GRAM.

But first off, you need to show exactly what colours you want to appear and where.

David.