t-display-s3 , readrect and readpixel issues

[nosmaster89]

hi i have recently aquired a t-display-s3 non-touch, im trying to read back areas of the screen , i have compiled a simple text that puts a bmp on half the screen, read back those pixels and then replay them to the other half of the screen

readRect seems to give me garbage in the buffer ,

readPixel gives me the correct data but its all color shifted

i have followed your guidace here setting spi and spi read to many different rates in user_setup_206 but this doesn't have any effect on the read pixels https://github.com/Bodmer/TFT_eSPI/discussions/951 TIA nos

[nosmaster89]

#include <TFT_eSPI.h>
#include <SPIFFS.h>
TFT_eSPI tft = TFT_eSPI();
const int WIDTH = 320;
const int HEIGHT = 170;
uint16_t read16(fs::File &f)
{
  uint16_t result;
  ((uint8_t *)&result)[0] = f.read(); // LSB
  ((uint8_t *)&result)[1] = f.read(); // MSB
  return result;
}
uint32_t read32(fs::File &f)
{
  uint32_t result;
  ((uint8_t *)&result)[0] = f.read(); // LSB
  ((uint8_t *)&result)[1] = f.read();
  ((uint8_t *)&result)[2] = f.read();
  ((uint8_t *)&result)[3] = f.read(); // MSB
  return result;
}
void drawBmp(const char *filename, int16_t x, int16_t y)
{
  Serial.println("Loading image '" + String(filename) + "'");
  if ((x >= tft.width()) || (y >= tft.height()))
  {

    Serial.println("Image is off screen");
    return;
  }

  fs::File bmpFS;

  // Open requested file on SD card
  bmpFS = SPIFFS.open(filename, "r");

  if (!bmpFS)
  {
    Serial.println("File not found");
    return;
  }

  uint32_t seekOffset;
  uint16_t w, h, row, col;
  uint8_t r, g, b;

  uint32_t startTime = millis();

  Serial.println("trying to load bmp file");
  if (read16(bmpFS) == 0x4D42)
  {
    Serial.println("found BMP file!");
    read32(bmpFS);
    read32(bmpFS);
    seekOffset = read32(bmpFS);
    read32(bmpFS);
    w = read32(bmpFS);
    h = read32(bmpFS);

    if ((read16(bmpFS) == 1) && (read16(bmpFS) == 24) && (read32(bmpFS) == 0))
    {
      y += h - 1;

      bool oldSwapBytes = tft.getSwapBytes();
      tft.setSwapBytes(true);
      bmpFS.seek(seekOffset);

      uint16_t padding = (4 - ((w * 3) & 3)) & 3;
      uint8_t lineBuffer[w * 3 + padding];

      for (row = 0; row < h; row++)
      {

        bmpFS.read(lineBuffer, sizeof(lineBuffer));
        uint8_t *bptr = lineBuffer;
        uint16_t *tptr = (uint16_t *)lineBuffer;
        // Convert 24 to 16-bit colours
        for (uint16_t col = 0; col < w; col++)
        {
          b = *bptr++;
          g = *bptr++;
          r = *bptr++;
          *tptr++ = ((r & 0xF8) << 8) | ((g & 0xFC) << 3) | (b >> 3);
        }

        // Push the pixel row to screen, pushImage will crop the line if needed
        // y is decremented as the BMP image is drawn bottom up
        tft.pushImage(x, y--, w, 1, (uint16_t *)lineBuffer);
      }
      tft.setSwapBytes(oldSwapBytes);
      Serial.print("Loaded in ");
      Serial.print(millis() - startTime);
      Serial.println(" ms");
    }
    else
      Serial.println("BMP format not recognized.");
  }
  Serial.println("File not loaded");
  bmpFS.close();
}
uint16_t *bmp_file = (uint16_t *)malloc(WIDTH * HEIGHT);

void convertBMP(String name)
{
  fs::File bmpFS;
  bmpFS = SPIFFS.open(name, "r");
  if (!bmpFS)
  {
    Serial.println("File not found");
    return;
  }
  uint32_t seekOffset;
  uint16_t w, h, row, col;
  uint8_t r, g, b;
  if (read16(bmpFS) == 0x4D42)
  {
    read32(bmpFS);
    read32(bmpFS);
    seekOffset = read32(bmpFS);
    read32(bmpFS);
    w = read32(bmpFS);
    h = read32(bmpFS);
    if ((read16(bmpFS) == 1) && (read16(bmpFS) == 24) && (read32(bmpFS) == 0))
    {
      bool oldSwapBytes = tft.getSwapBytes();
      tft.setSwapBytes(true);
      bmpFS.seek(seekOffset);
      uint16_t padding = (4 - ((w * 3) & 3)) & 3;
      uint8_t lineBuffer[w * 3 + padding];
      for (row = 0; row < h; row++)
      {
        bmpFS.read(lineBuffer, sizeof(lineBuffer));
        uint8_t *bptr = lineBuffer;
        uint16_t *tptr = (uint16_t *)lineBuffer;
        // Convert 24 to 16-bit colours
        for (uint16_t col = 0; col < w; col++)
        {
          b = *bptr++;
          g = *bptr++;
          r = *bptr++;
          *tptr++ = ((r & 0xF8) << 8) | ((g & 0xFC) << 3) | (b >> 3);
        }
      }
      tft.setSwapBytes(oldSwapBytes);
      // store it to bmp_file
      for (int i = 0; i < WIDTH / 2 * HEIGHT; i++)
      {
        bmp_file[i] = lineBuffer[i];
      }
    }
    else
      Serial.println("BMP format not recognized.");
  }
  bmpFS.close();
}

void setup()
{
  // init spiffs
  if (!SPIFFS.begin(true))
  {
    Serial.println("An Error has occurred while mounting SPIFFS");
    return;
  }
  Serial.begin(115200);
  Serial.println("TFT_eSPI test");
  tft.init();
  tft.setRotation(1);
  tft.setSwapBytes(true);
  Serial.println("TFT_eSPI test pattern");
  // tft.fillScreen(TFT_BLUE);
  tft.fillScreen(TFT_BLACK);
  Serial.println("TFT_eSPI pushImage");
  // get the test image from the spiffs img.png
  drawBmp("/img.bmp", 0, 0);
  Serial.println("TFT_eSPI readRect");
  convertBMP("/img.bmp");
  // read back the test pattern
  uint16_t *color_readback;
  color_readback = (uint16_t *)malloc(WIDTH * HEIGHT);
  // read in every pixel
  for (int i = 0; i < WIDTH / 2 * HEIGHT; i++)
  {
    color_readback[i] = tft.readPixel(i % (WIDTH / 2), i / (WIDTH / 2));
  }
  unsigned long bmp_file_length = sizeof(bmp_file) / sizeof(bmp_file[0]);
  int lines = bmp_file_length / (WIDTH / 2);
  Serial.println("lines " + String(lines));
  tft.setSwapBytes(false);
  for (int i = 0; i < WIDTH / 2 * HEIGHT; i++)
  {
    tft.drawPixel(i % (WIDTH / 2) + 170, i / (WIDTH / 2), color_readback[i]);
  }
}

void loop()
{
  Serial.println("loop");
  delay(1000);
}

here is the code i have used for this test