Add SPIFFS BMP (bitmap) image file rendering example

examples/Generic/TFT_SPIFFS_BMP/BMP_functions.ino

+// Bodmers BMP image rendering function
+
+void drawBmp(const char *filename, int16_t x, int16_t y) {
+
+  if ((x >= tft.width()) || (y >= tft.height())) return;
+
+  fs::File bmpFS;
+
+  // Open requested file on SD card
+  bmpFS = SPIFFS.open(filename, "r");
+
+  if (!bmpFS)
+  {
+    Serial.print("File not found");
+    return;
+  }
+
+  uint32_t seekOffset;
+  uint16_t w, h, row, col;
+  uint8_t  r, g, b;
+
+  uint32_t startTime = millis();
+
+  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))
+    {
+      y += h - 1;
+
+      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);
+      }
+      Serial.print("Loaded in "); Serial.print(millis() - startTime);
+      Serial.println(" ms");
+    }
+    else Serial.println("BMP format not recognized.");
+  }
+  bmpFS.close();
+}
+
+// These read 16- and 32-bit types from the SD card file.
+// BMP data is stored little-endian, Arduino is little-endian too.
+// May need to reverse subscript order if porting elsewhere.
+
+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;
+}
+

examples/Generic/TFT_SPIFFS_BMP/TFT_SPIFFS_BMP.ino

+// This sketch draws BMP images pulled from SPIFFS onto the TFT. It is an
+// an example from this library: https://github.com/Bodmer/TFT_eSPI
+
+// Images in SPIFFS must be put in the root folder (top level) to be found
+// Use the SPIFFS library example to verify SPIFFS works!
+
+// The example image used to test this sketch can be found in the sketch
+// Data folder, press Ctrl+K to see this folder. Use the IDE "Tools" menu
+// option to upload the sketches data folder to the SPIFFS
+
+// This sketch ahs been tested on the ESP32 and ESP8266
+
+//----------------------------------------------------------------------------------------------------
+
+//====================================================================================
+//                                  Libraries
+//====================================================================================
+// Call up the SPIFFS FLASH filing system this is part of the ESP Core
+#define FS_NO_GLOBALS
+#include <FS.h>
+
+#ifdef ESP32
+  #include "SPIFFS.h"  // For ESP32 only
+#endif
+
+// Call up the TFT library
+#include <TFT_eSPI.h> // Hardware-specific library for ESP8266
+
+// Invoke TFT library
+TFT_eSPI tft = TFT_eSPI();
+
+//====================================================================================
+//                                    Setup
+//====================================================================================
+void setup()
+{
+  Serial.begin(115200);
+
+  if (!SPIFFS.begin()) {
+    Serial.println("SPIFFS initialisation failed!");
+    while (1) yield(); // Stay here twiddling thumbs waiting
+  }
+  Serial.println("\r\nSPIFFS initialised.");
+
+  // Now initialise the TFT
+  tft.begin();
+  tft.setRotation(0);  // 0 & 2 Portrait. 1 & 3 landscape
+  tft.fillScreen(TFT_BLACK);
+}
+
+//====================================================================================
+//                                    Loop
+//====================================================================================
+void loop()
+{
+  int x = random(tft.width()  - 128);
+  int y = random(tft.height() - 160);
+
+  drawBmp("/parrot.bmp", x, y);
+
+  delay(1000);
+}
+//====================================================================================
+