Image viewer for VGA16fb framebuffer

Last update: 15.10.2006

Introduction

This small utility displays images in VGA16fb framebuffer.

Kernel module switches to mode 640x480x16, which is not supported by any program. It is caused by weird EGA video memory model---to put pixel(s) you have to reprogram video card!

I wrote two utilities: one displays only b/w images, and another that displays color images (but needs root privileges).

fbi16

This program runs at user level mode and relies on kernel module vga16fb settings. Fortunatelly the module leaves card in write mode 3, enables all planes, sets bit mask to 0xff, and do not reset color. We are able to put 8 pixels at once using the same, last used color (color of last putted char). Because of that fbi16 can display only b/w images.

The program displays PGM files. To view any image use shell script---it uses convert and pnmquant to produce b/w PGM files.

Compilation

gcc fbi16.c -o fbi16.bin

Usage

fbi16.bin file.pgm

Keyboard bindings

• q, Ctrl-C --- quit
• a --- scroll image left
• A --- scroll image left (faster)
• a --- scroll image right
• S --- scroll image right (faster)
• w --- scroll image down
• W --- scroll image dewn (faster)
• z --- scroll image up
• Z --- scroll image up (faster)
• i --- negative
• enter --- refresh image

Downloads

• fbi16.sh --- shell script
• fbi16.c --- source file

fbi16_2

This program needs root privileges, but can display 16 color images. It reads raw RGB images. To view any image use shell script---it uses convert to produce RGB files.

Warning: while scrolling image screen is flickering, and I do not any idea how to avoid it.

While displaying user can't switching consoles.

Compilation

gcc -O2 fbi16_2.c -o fbi16_2.bin

Flag -O2 is important (see man 3 outb).

Usage

fbi16_2.bin width height file.rgb

Keyboard bindings

• q, Ctrl-C --- quit
• a --- scroll image left
• A --- scroll image left (faster)
• a --- scroll image right
• S --- scroll image right (faster)
• w --- scroll image down
• W --- scroll image dewn (faster)
• z --- scroll image up
• Z --- scroll image up (faster)
• enter --- refresh image

Downloads

• fbi16_2.sh --- shell script
• fbi16_2.c --- source file

Author

Wojciech Muła, wojciech_mula@poczta.onet.pl