Hello,
I'm using a 3.5" TFT touchscreen. I'm on Arduino Uno but could also use a Mega.
I am trying to display images in bitmap format. The images are stored in a micro sd card.
The image appears on the screen.
Unfortunately the colors are not good.
I notice that it is the blue and red colors that are reversed (green is correct).
For example on this image: link
On the screen, there is blue instead of red, cyan instead of yellow...
How to get normal colors?
I already tried tft.invertDisplay(true); but the colors are even more false.
When I color the screen with fillScreen, the blue is indeed blue and the red is indeed red.
Here is some code I modified:
#include <Adafruit_TFTLCD.h>
#include <MCUFRIEND_kbv.h>
#include <Adafruit_GFX.h> // Core graphics library
#include <TouchScreen.h>
#include <Fonts/FreeMonoBoldOblique12pt7b.h>
#include <Fonts/FreeSansBold12pt7b.h>
#include <SPI.h>
#include <avr/pgmspace.h>
#include <SD.h>
#define SD_CS 10
const int XP=6,XM=A2,YP=A1,YM=7; //ID=0x9341
const int TS_LEFT=907,TS_RT=136,TS_TOP=942,TS_BOT=139;
TouchScreen ts = TouchScreen(XP, YP, XM, YM, 300);
TSPoint tp;
uint16_t ID, oldcolor, currentcolor;
#define BLACK 0x0000
#define BLUE 0x001F
#define RED 0xF800
#define GREEN 0x07E0
#define CYAN 0x07FF
#define MAGENTA 0xF81F
#define YELLOW 0xFFE0
#define WHITE 0xFFFF
#define ORANGE 0xFBE0
MCUFRIEND_kbv tft;
int x, y;
char currentPage;
void setup() {
Serial.begin(9600);
uint16_t tmp;
tft.reset();
ID = tft.readID();
tft.begin(ID);
tft.setRotation(1);
Serial.print("Initializing SD card...");
if (!SD.begin(SD_CS)) {
Serial.println("failed!");
return;
}
Serial.println("OK!");
tft.fillScreen(ORANGE);
delay(1000);
}
void loop() {
Homescreen();
while(1);
}
void Homescreen(){
bmpDraw("image.bmp",0,0);
delay(5000); }
#define BUFFPIXEL 20
void bmpDraw(char *filename, int x, int y) {
File bmpFile;
int bmpWidth, bmpHeight; // W+H in pixels
uint8_t bmpDepth; // Bit depth (currently must be 24)
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[BUFFPIXEL]; // pixel out buffer (16-bit per pixel)
uint8_t buffidx = sizeof(sdbuffer); // Current position in sdbuffer
boolean goodBmp = false; // Set to true on valid header parse
boolean flip = true; // BMP is stored bottom-to-top
int w, h, row, col;
uint8_t r, g, b;
uint32_t pos = 0, startTime = millis();
uint8_t lcdidx = 0;
boolean first = true;
if((x >= tft.width()) || (y >= tft.height())) return;
Serial.println();
Serial.print(F("Loading image '"));
Serial.print(filename);
Serial.println('\'');
// Open requested file on SD card
if ((bmpFile = SD.open(filename)) == NULL) {
Serial.println(F("File not found"));
return;
}
// Parse BMP header
if(read16(bmpFile) == 0x4D42) { // BMP signature
Serial.println(F("File size: ")); Serial.println(read32(bmpFile));
(void)read32(bmpFile); // Read & ignore creator bytes
bmpImageoffset = read32(bmpFile); // Start of image data
Serial.print(F("Image Offset: ")); Serial.println(bmpImageoffset, DEC);
// Read DIB header
Serial.print(F("Header size: ")); Serial.println(read32(bmpFile));
bmpWidth = read32(bmpFile);
bmpHeight = read32(bmpFile);
if(read16(bmpFile) == 1) { // # planes -- must be '1'
bmpDepth = read16(bmpFile); // bits per pixel
Serial.print(F("Bit Depth: ")); Serial.println(bmpDepth);
if((bmpDepth == 24) && (read32(bmpFile) == 0)) { // 0 = uncompressed
goodBmp = true; // Supported BMP format -- proceed!
Serial.print(F("Image size: "));
Serial.print(bmpWidth);
Serial.print('x');
Serial.println(bmpHeight);
// BMP rows are padded (if needed) to 4-byte boundary
rowSize = (bmpWidth * 3 + 3) & ~3;
// If bmpHeight is negative, image is in top-down order.
// This is not canon but has been observed in the wild.
if(bmpHeight < 0) {
bmpHeight = -bmpHeight;
flip = false;
}
// Crop area to be loaded
w = bmpWidth;
h = bmpHeight;
if((x+w-1) >= tft.width()) w = tft.width() - x;
if((y+h-1) >= tft.height()) h = tft.height() - y;
// 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).
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; col++) { // For each column...
// Time to read more pixel data?
if (buffidx >= sizeof(sdbuffer)) { // Indeed
// Push LCD buffer to the display first
if(lcdidx > 0) {
tft.pushColors(lcdbuffer, lcdidx, first);
lcdidx = 0;
first = false;
}
bmpFile.read(sdbuffer, sizeof(sdbuffer));
buffidx = 0; // Set index to beginning
}
// Convert pixel from BMP to TFT format
r = sdbuffer[buffidx++];
g = sdbuffer[buffidx++];
b = sdbuffer[buffidx++];
lcdbuffer[lcdidx++] = tft.color565(r,g,b);
} // end pixel
} // end scanline
// Write any remaining data to LCD
if(lcdidx > 0) {
tft.pushColors(lcdbuffer, lcdidx, first);
}
Serial.print(F("Loaded in "));
Serial.print(millis() - startTime);
Serial.println(" ms");
} // end goodBmp
}
}
bmpFile.close();
if(!goodBmp) Serial.println(F("BMP format not recognized."));
}
// 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(File f) {
uint16_t result;
((uint8_t *)&result)[0] = f.read(); // LSB
((uint8_t *)&result)[1] = f.read(); // MSB
return result;
}
uint32_t read32(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;
}