I'm currently working on a project where I need to display a bitmap image on a 3.2" TFT display (400x240 resolution) using an Arduino Uno. Unfortunately, I'm encountering some issues and could really use some help.
Problem Description:
-
The TFT display is showing a blank blue screen.
-
The serial monitor indicates that the image is being processed and loaded.
Hardware Setup:
- Arduino Uno
- 3.2" Open-Smart Display (400x240)
for code example that i use :
// MCUFRIEND UNO shields have microSD on pins 10, 11, 12, 13
// The official <SD.h> library only works on the hardware SPI pins
// e.g. 11, 12, 13 on a Uno (or STM32 Nucleo)
//
// copy all your BMP files to the root directory on the microSD with your PC
// (or another directory)
#include <SPI.h> // f.k. for Arduino-1.5.2
//#define USE_SDFAT
#include <SD.h> // Use the official SD library on hardware pins
#include <Adafruit_GFX.h> // Hardware-specific library
#include <MCUFRIEND_kbv.h>
MCUFRIEND_kbv tft;
#if defined(ESP32)
#define SD_CS 5
#else
#define SD_CS 10
#endif
#define NAMEMATCH "" // "" matches any name
//#define NAMEMATCH "tiger" // *tiger*.bmp
//#define PALETTEDEPTH 0 // do not support Palette modes
#define PALETTEDEPTH 8 // support 256-colour Palette
char namebuf[32] = "/"; //BMP files in root directory
//char namebuf[32] = "/bitmaps/"; //BMP directory e.g. files in /bitmaps/*.bmp
File root;
int pathlen;
void setup()
{
uint16_t ID;
Serial.begin(9600);
Serial.print("Show BMP files on TFT with ID:0x");
ID = tft.readID();
Serial.println(ID, HEX);
if (ID == 0x0D3D3) ID = 0x9481;
tft.begin(ID);
tft.fillScreen(0x001F);
tft.setTextColor(0xFFFF, 0x0000);
bool good = SD.begin(SD_CS);
if (!good) {
Serial.print(F("cannot start SD"));
while (1);
}
root = SD.open(namebuf);
pathlen = strlen(namebuf);
}
void loop()
{
char *nm = namebuf + pathlen;
File f = root.openNextFile();
uint8_t ret;
uint32_t start;
if (f != NULL) {
#ifdef USE_SDFAT
f.getName(nm, 32 - pathlen);
#else
strcpy(nm, (char *)f.name());
#endif
f.close();
strlwr(nm);
if (strstr(nm, ".bmp") != NULL && strstr(nm, NAMEMATCH) != NULL) {
Serial.print(namebuf);
Serial.print(F(" - "));
tft.fillScreen(0);
start = millis();
ret = showBMP(namebuf, 5, 5);
switch (ret) {
case 0:
Serial.print(millis() - start);
Serial.println(F("ms"));
delay(5000);
break;
case 1:
Serial.println(F("bad position"));
break;
case 2:
Serial.println(F("bad BMP ID"));
break;
case 3:
Serial.println(F("wrong number of planes"));
break;
case 4:
Serial.println(F("unsupported BMP format"));
break;
case 5:
Serial.println(F("unsupported palette"));
break;
default:
Serial.println(F("unknown"));
break;
}
}
}
else root.rewindDirectory();
}
#define BMPIMAGEOFFSET 54
#define BUFFPIXEL 20
uint16_t read16(File& f) {
uint16_t result; // read little-endian
f.read((uint8_t*)&result, sizeof(result));
return result;
}
uint32_t read32(File& f) {
uint32_t result;
f.read((uint8_t*)&result, sizeof(result));
return result;
}
uint8_t showBMP(char *nm, int x, int y)
{
File bmpFile;
int bmpWidth, bmpHeight; // W+H in pixels
uint8_t bmpDepth; // Bit depth (currently must be 24, 16, 8, 4, 1)
uint32_t bmpImageoffset; // Start of image data in file
uint32_t rowSize; // Not always = bmpWidth; may have padding
uint8_t sdbuffer[3 * BUFFPIXEL]; // pixel in buffer (R+G+B per pixel)
uint16_t lcdbuffer[(1 << PALETTEDEPTH) + BUFFPIXEL], *palette = NULL;
uint8_t bitmask, bitshift;
boolean flip = true; // BMP is stored bottom-to-top
int w, h, row, col, lcdbufsiz = (1 << PALETTEDEPTH) + BUFFPIXEL, buffidx;
uint32_t pos; // seek position
boolean is565 = false; //
uint16_t bmpID;
uint16_t n; // blocks read
uint8_t ret;
if ((x >= tft.width()) || (y >= tft.height()))
return 1; // off screen
bmpFile = SD.open(nm); // Parse BMP header
bmpID = read16(bmpFile); // BMP signature
(void) read32(bmpFile); // Read & ignore file size
(void) read32(bmpFile); // Read & ignore creator bytes
bmpImageoffset = read32(bmpFile); // Start of image data
(void) read32(bmpFile); // Read & ignore DIB header size
bmpWidth = read32(bmpFile);
bmpHeight = read32(bmpFile);
n = read16(bmpFile); // # planes -- must be '1'
bmpDepth = read16(bmpFile); // bits per pixel
pos = read32(bmpFile); // format
if (bmpID != 0x4D42) ret = 2; // bad ID
else if (n != 1) ret = 3; // too many planes
else if (pos != 0 && pos != 3) ret = 4; // format: 0 = uncompressed, 3 = 565
else if (bmpDepth < 16 && bmpDepth > PALETTEDEPTH) ret = 5; // palette
else {
bool first = true;
is565 = (pos == 3); // ?already in 16-bit format
// BMP rows are padded (if needed) to 4-byte boundary
rowSize = (bmpWidth * bmpDepth / 8 + 3) & ~3;
if (bmpHeight < 0) { // If negative, image is in top-down order.
bmpHeight = -bmpHeight;
flip = false;
}
w = bmpWidth;
h = bmpHeight;
if ((x + w) >= tft.width()) // Crop area to be loaded
w = tft.width() - x;
if ((y + h) >= tft.height()) //
h = tft.height() - y;
if (bmpDepth <= PALETTEDEPTH) { // these modes have separate palette
//bmpFile.seek(BMPIMAGEOFFSET); //palette is always @ 54
bmpFile.seek(bmpImageoffset - (4<<bmpDepth)); //54 for regular, diff for colorsimportant
bitmask = 0xFF;
if (bmpDepth < 8)
bitmask >>= bmpDepth;
bitshift = 8 - bmpDepth;
n = 1 << bmpDepth;
lcdbufsiz -= n;
palette = lcdbuffer + lcdbufsiz;
for (col = 0; col < n; col++) {
pos = read32(bmpFile); //map palette to 5-6-5
palette[col] = ((pos & 0x0000F8) >> 3) | ((pos & 0x00FC00) >> 5) | ((pos & 0xF80000) >> 8);
}
}
// Set TFT address window to clipped image bounds
tft.setAddrWindow(x, y, x + w - 1, y + h - 1);
for (row = 0; row < h; row++) { // For each scanline...
// Seek to start of scan line. It might seem labor-
// intensive to be doing this on every line, but this
// method covers a lot of gritty details like cropping
// and scanline padding. Also, the seek only takes
// place if the file position actually needs to change
// (avoids a lot of cluster math in SD library).
uint8_t r, g, b, *sdptr;
int lcdidx, lcdleft;
if (flip) // Bitmap is stored bottom-to-top order (normal BMP)
pos = bmpImageoffset + (bmpHeight - 1 - row) * rowSize;
else // Bitmap is stored top-to-bottom
pos = bmpImageoffset + row * rowSize;
if (bmpFile.position() != pos) { // Need seek?
bmpFile.seek(pos);
buffidx = sizeof(sdbuffer); // Force buffer reload
}
for (col = 0; col < w; ) { //pixels in row
lcdleft = w - col;
if (lcdleft > lcdbufsiz) lcdleft = lcdbufsiz;
for (lcdidx = 0; lcdidx < lcdleft; lcdidx++) { // buffer at a time
uint16_t color;
// Time to read more pixel data?
if (buffidx >= sizeof(sdbuffer)) { // Indeed
bmpFile.read(sdbuffer, sizeof(sdbuffer));
buffidx = 0; // Set index to beginning
r = 0;
}
switch (bmpDepth) { // Convert pixel from BMP to TFT format
case 32:
case 24:
b = sdbuffer[buffidx++];
g = sdbuffer[buffidx++];
r = sdbuffer[buffidx++];
if (bmpDepth == 32) buffidx++; //ignore ALPHA
color = tft.color565(r, g, b);
break;
case 16:
b = sdbuffer[buffidx++];
r = sdbuffer[buffidx++];
if (is565)
color = (r << 8) | (b);
else
color = (r << 9) | ((b & 0xE0) << 1) | (b & 0x1F);
break;
case 1:
case 4:
case 8:
if (r == 0)
b = sdbuffer[buffidx++], r = 8;
color = palette[(b >> bitshift) & bitmask];
r -= bmpDepth;
b <<= bmpDepth;
break;
}
lcdbuffer[lcdidx] = color;
}
tft.pushColors(lcdbuffer, lcdidx, first);
first = false;
col += lcdidx;
} // end cols
} // end rows
tft.setAddrWindow(0, 0, tft.width() - 1, tft.height() - 1); //restore full screen
ret = 0; // good render
}
bmpFile.close();
return (ret);
}
the serial Monitor Output
Show BMP files on TFT with ID:0x5252
/tiger.bmp - 2193ms