A C library for manipulating bitmap/raster graphics in memory and on disk.
#include <stdio.h>
#include "bmp.h"
int main(int argc, char *argv[]) {
Bitmap *b = bm_create(128,128);
bm_set_color(b, bm_atoi("white"));
bm_puts(b, 30, 60, "Hello World");
bm_save(b, "out.gif");
bm_free(b);
return 0;
}
The code is licensed under the terms of the MIT-0 License. See the file LICENSE for details.
Attribution is appreciated, but not required.
Features:
- Supported formats:
- Windows BMP: loads 4-, 8- and 24-bit uncompressed BMP files, saves as 24-bit.
- GIF, PCX and TGA files can be loaded and saved without third-party dependencies.
- PNG through libpng
- support for palettized images is incomplete.
- JPEG through libjpeg
- Alternatively, PNG and JPEG files can be loaded through the Sean Barrett's
stb_image image loader library. stb_image supports a couple of
additional formats, such as PSD, PIC and PNM binary formats. See
bm_load_stb()
for more information. A copy ofstb_image.h
has been placed in/3rd-party/stb_image.h
. - Likewise, PNG and JPEG images can be saved through Sean Barrett's
stb_image_write image writer library.
A copy of
stb_image_write.h
has been placed in/3rd-party/stb_image_write.h
. - NetPBM formats (PBM, PGM and PPM), in ASCII or binary variants.
- Supports manipulation of OpenGL textures, SDL
surfaces, GDI
contexts. See the
bm_bind()
function. It can also serve as a back end for Cairo graphics - Support for SDL2's
SDL_RWops
file manipulation routines for loading images in the supported formats. - Primitives: Lines, circles, elipses, bezier curves, polygons, etc.
- Clipping rectangles are obeyed.
- Floodfill and filled primitives.
- Image resizing: nearest neighbour, bilinear and bicubic.
- Blitting, blitting with color masks, scaled and rotated blitting.
- Text rendering: FreeType support and built-in 8-bit style raster fonts, and support for SFont and GrafX2-style fonts.
- Filtering with kernels and smoothing.
- CSS-style colors.
- Loading images from XBM and X PixMap data.
- Cross platform. It's been known to compile under Windows (MinGW), Linux, Android and Web via Emscripten.
The fonts/
directory contains some 8-bit style bitmap fonts in XBM format.
Copy bmp.c
and bmp.h
to your project directory, and add bmp.c
to your
list of files to compile.
To enable PNG support you need zlib and libpng (the development versions) installed. If you are using GCC, do the following:
- Use these flags
-DUSEPNG `libpng-config --cflags`
when compiling. - Add
`libpng-config --ldflags` -lz
when linking.
Other compilers might have diffent flags. See the libpng documentation for your platform.
Likewise, to enable JPEG support, you need libjpeg installed and specify
the -DUSEJPG
command line option when compiling and add -ljpeg
to your
linker options.
To use stb_image, put the stb_image.h
file in the same directory as
bmp.c
(or use your compiler's -I
option to point it to stb_image.h
's
path), and add -DUSESTB
to your compiler flags.
Similarly, to use stb_image_write, put the stb_image_write.h
file in the
same directory as bmp.c
, and add -DUSESTBW
to your compiler flags.
Use bm_create()
to create Bitmap
objects and bm_free()
to destroy them.
bm_bind()
can be used to wrap a Bitmap object around an existing buffer of
bytes, such as OpenGL textures and SDL surfaces.
The Makefile
generates HTML documentation from bmp.h
through the
d.awk script. Type make docs
to create the documentation.
A basic CMakeLists.txt
file is also provided for CMake, but you might need
to adapt it to your specific needs. To build with CMake, use the following commands:
mkdir build; cd build
cmake -G "Unix Makefiles" ..
make
- The
fonts/
directory contains some 8ร8 bitmap fonts in XBM format that can be loaded via thebm_make_xbm_font()
function.- Most of the fonts are based on 80's home computers, drawn from the examples at http://damieng.com/blog/2011/02/20/typography-in-8-bits-system-fonts
- The
INSTRUCTIONS
file contains information for using them. - The
tomthumb.c
file contains a 4ร6 font based on the "Tom Thumb" monospace font at http://robey.lag.net/2010/01/23/tiny-monospace-font.html
- The
ftypefont/
directory contains a wrapper for FreeType to allow rendering of freetype-supported fonts onBitmap
structures. - The
misc/
directory containsgif.c
andgif.h
- code for programmatically manipulating animated GIFs. It originates from the file I used to develop the GIF encoder/decoder originally.cairoback.c
- A demo of how the bitmap objects can be used as a back-end for the Cairo graphics library- The
palette/
subdirectory contains a utility for generating palettes and converting images to those palettes. xpm.c
: Samples on how to use the module with the XPM file format.to_xbm.c
contains a function that can output a bitmap as a XBM.- The
kmeans.c
contains a program that uses K-means clustering to identify the dominant colors in an image. imgdup.c
is a program that scans directories for duplicate images using the dHash algorithm.nanosvg.c
is an example of how to use the library with Mikko Mononen's NanoSVG library to load SVG files.bm_microui.c
contains functions to renderrxi
's microui graphical user interfaces to aBitmap
structure.cp437.c
andcp437.h
contains a Code page 437BmFont
and some utility functions to draw a grid-based TUI screen.bdffont.c
contains code to load and draw BDF fonts asBmFont
objects.bgichr.h
is a set of functions that can handle old Borland BGI fonts (usually files with a.CHR
extension) asBmFont
objects.
- BMP file format on Wikipedia
- Bresenham's line algorithm on Wikipedia
- http://members.chello.at/~easyfilter/bresenham.html
- Flood fill on Wikipedia
- Midpoint circle algorithm on Wikipedia
- http://web.archive.org/web/20110706093850/http://free.pages.at/easyfilter/bresenham.html
- Typography in 8 bits: System fonts
- GIF89a specification
- Nelson, M.R. : "LZW Data Compression", Dr. Dobb's Journal, October 1989.
- http://commandlinefanatic.com/cgi-bin/showarticle.cgi?article=art011
- What's In A GIF by Matthew Flickinger
- http://web.archive.org/web/20100206055706/http://www.qzx.com/pc-gpe/pcx.txt
- http://www.shikadi.net/moddingwiki/PCX_Format
- Truevision TGA on Wikipedia
- http://paulbourke.net/dataformats/tga/
- http://www.ludorg.net/amnesia/TGA_File_Format_Spec.html
- X PixMap on Wikipedia
- A simple libpng example program
- http://www.fileformat.info/format/xpm/egff.htm
- "Fast Bitmap Rotation and Scaling" By Steven Mortimer, Dr Dobbs' Journal,
July 01, 2001
http://www.drdobbs.com/architecture-and-design/fast-bitmap-rotation-and-scaling/184416337 - http://www.efg2.com/Lab/ImageProcessing/RotateScanline.htm
- Image Filtering in Lode's Computer Graphics Tutorial
- Grayscale on Wikipedia
- Xiaolin Wu's line algorithm on Wikipedia.
- Michael Abrash's article in the June 1992 issue of Dr Dobbs' Journal.
- The
README
file in the SFont distribution discusses the details. - This forum post contains a discussion of the GrafX2 format
- Here are some SFont/GrafX2 font resources:
- Support for PCF fonts (now that I support BDF fonts).
- If I'm going to have
bm_rotate_cw()
andbm_rotate_ccw()
functions, then I ought to have flip horizontal and vertical functions as well for completeness. - Since
bm_rotate_cw()
andbm_rotate_ccw()
functions take the clipping rect into account, I should consider doing the same for some of the other API functions for consistency, likebm_resample()
and co. Also the flip functions suggested above.