Arduino drawing a bitmap on nokia 5110 lcd

Question

Hello I finally got my nokia 5110 lcd working, I have tested it by displaying bitmap images other people have made. I made my own image and then used lcd assistant to turn it into an array. First look at my code.

#include "U8glib.h"

U8GLIB_PCD8544 u8g(8, 4, 7, 5, 6); // CLK=8, DIN=4, CE=7, DC=5, RST=6

int x = 5; int y = 5;

int level = 5;

const uint8_t rook_bitmap[] U8G_PROGMEM = { 0x7E, 0x82, 0x04, 0x8E, 0x7A, 0x42, 0xB4, 0x24, 0x08, 0xD8, 0x48, 0x08, 0x08, 0x0C, 0x02, 0x22, 0xD9, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x1E, 0x11, 0x21, 0x22, 0x14, 0x3B, 0xD4, 0x25, 0x29, 0x68, 0xA8, 0xA8, 0x74, 0x0C, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, };

void draw(void) { // graphic commands to redraw the complete screen should be placed here
u8g.drawBitmapP( 5, 5, 3,18, rook_bitmap);

}

void setup(void) {

}

void loop(void) { // picture loop u8g.firstPage();
do { draw(); } while( u8g.nextPage() );

// y++; // rebuild the picture after some delay delay(1000); }

The part that goes wrong is at u8g.drawBitmapP(5,5,21,18, rook_bitmap); I know it is to do with the 21 and 18 being wrong because I don't know where to get those numbers. Is it the width and height of the image when it is in paint.net or what is it?

Answer 1

The 21 and 18 are the dimensions of the image. It's not just pixels though.

The first number (21) is the number of bytes in a row of the image - that is one eighth of the width in pixels. The width must be a multiple of 8.

The second number is the number of rows in the image - basically the height in pixels.

The two numbers, when multiplied together, must equal the number of bytes in your array.

From the documentation:

Description

Draw a bitmap at the specified x/y position (upper left corner of the bitmap). Parts of the bitmap may be outside the display boundaries. The bitmap is specified by the array bitmap. A cleared bit means: Do not draw a pixel. A set bit inside the array means: Write pixel with the current color index. For a monochrome display, the color index 0 will usually clear a pixel and the color index 1 will set a pixel.

Arguments:

• u8g : Pointer to the u8g structure (C interface only).
• x: X-position (left position of the bitmap).
• y: Y-position (upper position of the bitmap).
• cnt: Number of bytes of the bitmap in horizontal direction. The width of the bitmap is cnt*8.
• h: Height of the bitmap.

---

It would appear your image data is complete gibberish. This is what I decode it to be:

 ######  #     #  #     
 ###   # # ####  #    # 
  # ## #  #  #     #    
   ## ##   #  #    #    
   #      ##     #      
 #   #  #  ## #####     


        #        ####   
#   #   #    #   #   #  
  # #   ## ###    # # ##
# #  #  #  # #     # ## 
   # # #   # # #  # ### 
  ##    ##