BmpHandleVerilog

This is an easy to use BMP (Microsoft Bitmap) handling Verilog tasks.

License

This is licensed with the 3-clause BSD license to make the library useful in open and closed source products independent of their licensing scheme.

1. Quick start

   1) go to '$ cd sim/modelsim'
   2) run '$ make cleanup' and then '$ make'
      . It may take time depending on size of image and filter.
      . Set 'BMP_INPUT_FILE' macro in 'Makefile' to change image.
   3) preview 'result.bmp'
      '$ display result.bmp' on Ubuntu.
   

Note that it works with ModelSim and icarus Verilog, but does not work with Vivado Sim due to $fwriteb() bug.

2. Basic usage

2.1 TO READ

   1) open a BMP file
        fd_input = $fopen(bmp_input_file_name, "rb");
   2) read BMP
        bmp_read(fd_input, code);
      this step fills 'bmp_file_header[]', 'bmp_image_header[]', 'pBitMap[]' and others.
   3) close the BMP file if no futher use
        $fclose(fd_input);
   4) do your operation on 'pBitMap[0:biSizeImage-1]',
      which is 8-bit array containing BGR color components.
      E.g., pBitMap[0] will be Blue of the first pixel,
            pBitMap[1] will be Green of the first pixel,
            pBitMap[2] will be Red of the first pixel,
            pBitMap[N*3] will be Blue of the N-th pixel,
            pBitMap[N*3+1] will be Green of the N-th pixel,
            pBitMap[N*3+2] will be Red of the N-th pixel.
   

2.2 TO WRITE

   1) open a file to store BMP
        fd_output = $fopen(bmp_output_file_name, "wb");
   2) fills 'bmp_file_header[]', 'bmp_image_header[]', 'pBitMap[]'
        bmp_gen_file_header(); bmp_gen_img_header(); ...
   3) write file
        bmp_write(fd_output, code);
        $fclose(fd_output);
   

3. Edge detection example

                     mod_bmp       mod_mem       mod_edge
   +-----+          +---------+    +--------+    +--------+
   |BMP  |---read-->|         |    |        |    |        |
   |     |          |         |    |        |    |        |
   +-----+          |         |--->|        |--->|        |
                    |         |    |        |    |        |
   +-----+          |         |<---|        |<---|        |
   |BMP  |<--write--|         |    |        |    |        |
   |     |          |tasks_bmp|    |        |    |        |
   +-----+          +---------+    +--------+    +--------+
                         ||            ||             ||
                    +-------------------------------------+
                    |           control                   |
                    +-------------------------------------+

'top.v' controls overall steps by using handshake signals. 'mod_bmp.v' first reads BMP file and writes bitmaps to 'mod_mem' using task call. 'mod_edge.v' first read BMP from 'mod_mem' and performs edge detection and then writes the result to 'mod_mem'. 'mod_bmp.v' reads bitmap result and then writes to BMP file.

4. Revision history

• 2020.07.31: 'bmp_get_red()/green()/blue()' of 'tasks_bmp.v' added.
• 2020.07.30: bug cased by 'biSizeImage=0' has been fixed.
• 2018.08.03: 'bmp_read_img_header()' of 'tasks_bmp.v' has been update to support ImageHead Version 4.