support_functions.h

#include <math.h>

#include "pngle.h"

#define LINE_BUF_SIZE 64  // pixel = 524, 16 = 406, 32 = 386, 64 = 375, 128 = 368, 240 = 367, no draw = 324 (51ms v 200ms)
int16_t px = 0, sx = 0;
int16_t py = 0, sy = 0;
uint8_t pc = 0;
uint16_t lbuf[LINE_BUF_SIZE];

 int16_t png_dx = 0, png_dy = 0;

// Define corner position
void setPngPosition(int16_t x, int16_t y)
{
  png_dx = x;
  png_dy = y;
}

// Draw pixel - called by pngle
void pngle_on_draw(pngle_t *pngle, uint32_t x, uint32_t y, uint32_t w, uint32_t h, uint8_t rgba[4])
{
  uint16_t color = (rgba[0] << 8 & 0xf800) | (rgba[1] << 3 & 0x07e0) | (rgba[2] >> 3 & 0x001f);

#if !defined(USE_ADAFRUIT_GFX) && defined(USE_LINE_BUFFER)
  color = (color << 8) | (color >> 8);
#endif

  if (rgba[3] > 127) { // Transparency threshold (no blending yet...)

  #ifdef USE_LINE_BUFFER // This must handle skipped pixels in transparent PNGs
    if ( pc >= LINE_BUF_SIZE) {
      #ifdef USE_ADAFRUIT_GFX
        tft.drawRGBBitmap(png_dx + sx, png_dy + sy, lbuf, LINE_BUF_SIZE, 1);
      #else
        tft.pushImage(png_dx + sx, png_dy + sy, LINE_BUF_SIZE, 1, lbuf);
      #endif
      px = x; sx = x; sy = y; pc = 0;
    }

    if ( (x == px) && (sy == y) && (pc < LINE_BUF_SIZE) ) {px++; lbuf[pc++] = color;}
    else {
      #ifdef USE_ADAFRUIT_GFX
        tft.drawRGBBitmap(png_dx + sx, png_dy + sy, lbuf, pc, 1);
      #else
        tft.pushImage(png_dx + sx, png_dy + sy, pc, 1, lbuf);
      #endif
      px = x; sx = x; sy = y; pc = 0;
      px++; lbuf[pc++] = color;
    }
  #else
    tft.drawPixel(x, y, color);
  #endif
  }
}

// Render from SPIFFS or SD
void load_file(fs::FS &fs, const char *path)
{
  fs::File file = fs.open(path);
  if (!file) {
    Serial.println("Failed to open file for reading");
    return ;
  }

  pngle_t *pngle = pngle_new();
  pngle_set_draw_callback(pngle, pngle_on_draw);

  // Feed data to pngle
  uint8_t buf[1024];

  int remain = 0;
  int len;
  #if !defined(USE_ADAFRUIT_GFX) && !defined(USE_LINE_BUFFER)
   tft.startWrite(); // Crashes Adafruit_GFX
  #endif

  while ((len = file.read(buf + remain, sizeof(buf) - remain)) > 0) {
    int fed = pngle_feed(pngle, buf, remain + len);
    if (fed < 0) {
      Serial.printf("ERROR: %s\n", pngle_error(pngle));
      break;
    }

    remain = remain + len - fed;
    if (remain > 0) memmove(buf, buf + fed, remain);
  }
#ifdef USE_LINE_BUFFER
   // Draw any remaining pixels - had no warning that image has ended...
  if (pc) {
  #ifdef USE_ADAFRUIT_GFX
    tft.drawRGBBitmap(png_dx + sx, png_dy + sy, lbuf, pc, 1);
  #else
    tft.pushImage(png_dx + sx, png_dy + sy, pc, 1, lbuf);
  #endif
    pc = 0;
  }
#endif
  #if !defined(USE_ADAFRUIT_GFX) && !defined(USE_LINE_BUFFER)
    tft.endWrite();
  #endif
  pngle_destroy(pngle);
  file.close();
}


void load_png(const char *url)
{
  HTTPClient http;

  http.begin(url);

  int httpCode = http.GET();
  if (httpCode != HTTP_CODE_OK) {
    Serial.printf("HTTP ERROR: %d\n", httpCode);
    http.end();
    return ;
  }
  int total = http.getSize();

  WiFiClient *stream = http.getStreamPtr();

  pngle_t *pngle = pngle_new();
  pngle_set_draw_callback(pngle, pngle_on_draw);

  uint8_t buf[1024];
  int remain = 0;
  int len;
  uint32_t timeout = 0;

  #if !defined(USE_ADAFRUIT_GFX) && !defined(USE_LINE_BUFFER)
    tft.startWrite(); // Crashes Adafruit_GFX
  #endif
  while (http.connected() && (total > 0 || total == -1)) {
    size_t size = stream->available();

    if (timeout > 500) break;
    if (!size) { delay(2); timeout++;  continue; }
    if (size > sizeof(buf) - remain) size = sizeof(buf) - remain;

    if ((len = stream->readBytes(buf + remain, size)) > 0) {
      int fed = pngle_feed(pngle, buf, remain + len);
      if (fed < 0) {
        Serial.printf("ERROR: %s\n", pngle_error(pngle));
        break;
      }
      remain = remain + len - fed;
      if (remain > 0) memmove(buf, buf + fed, remain);
      total -= len;
    }
  }
#ifdef USE_LINE_BUFFER
  // Draw any remaining pixels
  if (pc) {
  #ifdef USE_ADAFRUIT_GFX
    tft.drawRGBBitmap(png_dx + sx, png_dy + sy, lbuf, pc, 1);
  #else
    tft.pushImage(png_dx + sx, png_dy + sy, pc, 1, lbuf);
  #endif
    pc = 0;
  }
#endif
  #if !defined(USE_ADAFRUIT_GFX) && !defined(USE_LINE_BUFFER)
    tft.endWrite();
  #endif
  pngle_destroy(pngle);
  http.end();
}