I purchased a 4.3inch LCD display and Arduino shield from BuyDisplay (https://www.buydisplay.com/low-cost-lcd-display-4-3-inch-arduino-spi-i2c-tft-touchscreen-800x480 and it works just fine with the supplied (downloaded) files on a UNO when it comes to rendering vector graphics, but there's a problem with the unit displaying bitmaps, or at least the bitmaps supplied as part of the download.
They display ok, but each takes around a minute to load, line by line. If I modify (increase) the memory buffer size in the supplied sketch, it simply bricks and I have to do a complete reset. The supplied graphics are 800x480, 96dpi as far as I can make out, but unfortunately if I reduce the resolution of the files, the sketch responds with "BMP format not recognised).
As a complete newcomer to the display side of the hobby, I really don't know how to manipulate the graphic files to make them load faster. I also can't get my tiny brain around the library used either I'm afraid!
Can anyone offer me any ideas I could try to speed up the image loading? I've attached the code I'm using.
/***************************************************
//Web: http://www.buydisplay.com
EastRising Technology Co.,LTD
Examples for ER-TFTMC043-7 SDcard(bitmap) test
Display is Hardward SPI 4-Wire SPI Interface and 5V Power Supply
Tested and worked with:
Works with Arduino 1.6.0 IDE
Test ok: Arduino Due,Arduino UNO,Arduino MEGA2560
****************************************************/
#include <SD.h>
#include <SPI.h>
#include <Wire.h>
#include "TFTMC043_7.h"
#define sd_cs 5
void setup() {
Serial.begin(9600);
if (!SD.begin(sd_cs))
{
Serial.println("initialization failed!");
return;
}
Serial.println("initialization done.");
ER5517.Parallel_Init();
ER5517.HW_Reset();
ER5517.System_Check_Temp();
delay(100);
while(ER5517.LCD_StatusRead()&0x02);
ER5517.initial();
ER5517.Display_ON();
pinMode(2, OUTPUT);
digitalWrite(2, HIGH);////Disable SD RTP
}
void loop() {
ER5517.Select_Main_Window_16bpp();
ER5517.Main_Image_Start_Address(layer1_start_addr);
ER5517.Main_Image_Width(LCD_XSIZE_TFT);
ER5517.Main_Window_Start_XY(0,0);
ER5517.Canvas_Image_Start_address(0);
ER5517.Canvas_image_width(LCD_XSIZE_TFT);
ER5517.Active_Window_XY(0,0);
ER5517.Active_Window_WH(LCD_XSIZE_TFT,LCD_YSIZE_TFT);
ER5517.Foreground_color_65k(Blue);
ER5517.Line_Start_XY(0,0);
ER5517.Line_End_XY(LCD_XSIZE_TFT-1,LCD_YSIZE_TFT-1);
ER5517.Start_Square_Fill();
ER5517.Foreground_color_65k(White);
ER5517.Background_color_65k(Red);
ER5517.CGROM_Select_Internal_CGROM();
ER5517.Font_Select_12x24_24x24();
ER5517.Goto_Text_XY(0,0);
ER5517.Show_String( "www.buydisplay.com");
bmpDraw("BMP_1.bmp", 0, 0);
delay(1000);
bmpDraw("BMP_2.bmp", 0, 0);
delay(1000);
bmpDraw("BMP_3.bmp", 0, 0);
delay(1000);
bmpDraw("BMP_4.bmp", 0, 0);
delay(1000);
bmpDraw("BMP_5.bmp", 0, 0);
delay(1000);
bmpDraw("BMP_6.bmp", 0, 0);
delay(1000);
bmpDraw("BMP_7.bmp", 0, 0);
delay(1000);
bmpDraw("BMP_8.bmp", 0, 0);
delay(1000);
bmpDraw("BMP_9.bmp", 0, 0);
delay(1000);
bmpDraw("BMP_10.bmp", 0, 0);
delay(1000);
}
// This function opens a Windows Bitmap (BMP) file and
// displays it at the given coordinates. It's sped up
// by reading many pixels worth of data at a time
// (rather than pixel by pixel). Increasing the buffer
// size takes more of the Arduino's precious RAM but
// makes loading a little faster. 20 pixels seems a
// good balance.
#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 >= LCD_XSIZE_TFT) || (y >= LCD_YSIZE_TFT)) 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) >= LCD_XSIZE_TFT) w = LCD_XSIZE_TFT - x;
if((y+h-1) >= LCD_YSIZE_TFT) h = LCD_YSIZE_TFT - y;
// Set TFT address window to clipped image bounds
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) {
ER5517.DrawPixel(col, row, lcdbuffer[lcdidx]);
lcdidx = 0;
first = false;
}
bmpFile.read(sdbuffer, sizeof(sdbuffer));
buffidx = 0; // Set index to beginning
}
// Convert pixel from BMP to TFT format
b = sdbuffer[buffidx++];
g = sdbuffer[buffidx++];
r = sdbuffer[buffidx++];
lcdbuffer[lcdidx] = color565(r,g,b);
ER5517.DrawPixel(col, row, lcdbuffer[lcdidx]);
} // end pixel
} // end scanline
// Write any remaining data to LCD
if(lcdidx > 0) {
ER5517.DrawPixel(col, row, lcdbuffer[lcdidx]);
}
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;
}
uint16_t color565(uint8_t r, uint8_t g, uint8_t b) {
return ((r & 0xF8) << 8) | ((g & 0xFC) << 3) | (b >> 3);
}
byte decToBcd(byte val){
// Convert normal decimal numbers to binary coded decimal
return ( (val/10*16) + (val%10) );
}
The TFTMC043_7.h file is fairly big (over 77000 characters), but I can add it if needed (if it'll fit!!).
TIA