Png2prg converts a 320x200 image (png/gif/jpeg) to a c64 hires or multicolor bitmap, charset or sprites prg. It will find the best matching palette and backgroundcolor automatically, no need to modify your source images or configure a palette. Vice screenshots with default borders (384x272) are automatically cropped. Vice's main screen's offset is at x=32, y=35. Images in sprite dimensions will be converted to sprites.
The resulting .prg includes the 2-byte start address and optional displayer. The displayers for koala, hires, mcibitmap and animations include fullscreen fade-in/out and optionally a .sid tune.
This tool can be used in all buildchains on most platforms.
Png2prg is not a tool to wire fullcolor images. It needs input images to already be compliant with c64 color and size restrictions. In verbose mode (-v) it outputs locations of color clashes, if any.
If you do need to wire fullcolor images, check out Youth's Retropixels.
koala: multicolor bitmap (max 4 colors per char)
hires: singlecolor bitmap (max 2 colors per char)
mccharset: multicolor charset (max 4 colors)
sccharset: singlecolor charset (max 2 colors)
mcsprites: multicolor sprites (max 4 colors)
scsprites: singlecolor sprites (max 2 colors)
mcibitmap: 320x200 multicolor interlace bitmap (max 4 colors per char/frame)
Png2prg is mostly able to autodetect the correct graphics mode, but you can also force a specific graphics mode with the -mode flag:
./png2prg -m koala image.png
Bitmap: $2000 - $3f3f
Screen: $3f40 - $4327
D020: $4328 (singlecolor only)
D800: $4328 - $470f (multicolor only)
D021: $4710 (multicolor only, low-nibble)
D020: $4710 (multicolor only, high-nibble)
Experimental interlace support, you can supply one 320x200 multicolor image with max 4 colors per 8x8 pixel char per frame of which at least 2 are shared (the D021 and D800 colors).
Or supply both frames in regular koala specs (-interlace flag required). When making screenshots in vice, please disable the d016 pixel shift manually.
./png2prg -i testdata/madonna/frame_0.png testdata/madonna/frame_1.png
./png2prg testdata/madonna/cjam_pure_madonna.png
D800: $5800 - $5be7
Screen: $5c00 - $5fe7
Bitmap1: $6000 - $7f3f
D021: $7f40 (low-nibble)
D020: $7f40 (high-nibble)
D016Offset: $7f42
Bitmap2: $8000 - $9f3f
./png2prg -i -d016 1 testdata/mcinterlace/parriot?.png
Screen1: $9c00 - $9fe7
D021: $9fe8 (low-nibble)
D020: $9fe8 (high-nibble)
D016Offset: $9fe9
Bitmap1: $a000 - $bf3f
Bitmap2: $c000 - $df3f
Screen2: $e000 - $e3e7
D800: $e400 - $e7e7
Currently only images with max 4 colors can be converted into a charset. Support for individual d800 colors and mixed single/multicolor chars may be added in a future release, if the need arises.
By default charsets are packed, they only contain unique characters. If you do not want charpacking, eg for a 1x1 charset, please use -no-pack
Charset: $2000-$27ff
Screen: $2800-$2be7
CharColor: $2be8
D021: $2be9
D022: $2bea (multicolor only)
D023: $2beb (multicolor only)
D020: $2bec (multicolor only)
If the source image size is a multiple of a 24x21 pixel sprite, the image is considered to contain sprites.
The image will be converted left to right, top to bottom.
Sprite 1: $2000-$203f
Sprite 2: $2040-$207f
...
By default, png2prg guesses bitpair colors by itself. In most cases you don't need to configure anything. It will provide a mostly normalized image which should yield good pack results, but your miles may vary.
To give you more control, you can force/prefer a specific bitpair color-order. Use c64 colors, so 0 for black, 1 for white, 2 for red, etc.
The following example will force background color 0 for bitpair 00 and prefer colors 6,14,3 for bitpairs 01,10,11:
./png2prg -bitpair-colors 0,6,14,3 image.png
It's also possible to explicitly skip certain bitpair preferences with -1:
./png2prg -bitpair-colors 0,-1,-1,3 image.png
Each frame will be concatenated in the output .prg. You can supply an animated .gif or multiple image files.
If multiple files are added, they are treated as animation frames. You can also supply an animated .gif. The first image will be exported with all framedata appended. Koala animation frames start at $4711, hires at $4329.
The frame files are following this format. Each frame consists of 1 or more chunks. A chunk looks like this:
.byte $03 // number of chars in this chunk
// $00 marks end of frame
// $ff marks end of all frames
.word bitmap // bitmap address of this chunk (the high byte is <$20)
.word screen // screenram address (the high byte is <$04)
For each char in this chunk:
.byte 0,31,15,7,8,34,0,128 // pixels
.byte $64 // screenram colors
.byte $01 // colorram color (koala only)
... // next char(s)
... // next chunks
.byte 0 // end of frame
... // next frame(s)
.byte $ff // end of all frames
The -d or -display flag will link displayer code infront of the picture. By default it will also crunch the resulting file with Antonio Savona's TSCrunch with a couple of changes in my own fork.
For hires, koala and koala-anim the displayer also supports adding a .sid. Multispeed sids are supported as long as the .sid initializes the CIA timers correctly.
You can use sids located from $0e00-$1fff or $e000+ in the displayers. More areas may be free depending on graphics type. A memory usage map is shown on error and in -vv (very verbose) mode.
If needed, you can relocate most sids using lft's sidreloc.
Zeropages $08-$0f are used in the animation displayers, while none are used in hires/koala displayers, increasing sid compatibility.
This release contains examples with all assets included for you to test with. Also included are the assets of Évoluer by The Sarge and Flotsam.
First install Go 1.20 or higher, then:
go install github.com/staD020/png2prg/cmd/png2prg@latest
Png2prg was built on Linux, building on Mac should work out of the box. For Windows, try out Windows Subsystem Linux (WSL), works pretty well. However, natively building on Windows should be easy enough, look at Compiling without Make below.
The compiled displayer prgs are included in the repo to ease building and importing png2prg as a library. Java is only required to build the displayers with KickAssembler (included in the repo).
make -j
Build for all common targets:
make all -j
go build ./cmd/png2prg
In your Go project's path, go get the library:
go get github.com/staD020/png2prg
In essence png2prg implements the io.WriterTo interface. Typical usage could look like below. A more complex example can be found in the source of the cli tool.
import (
"fmt"
"io"
"github.com/staD020/png2prg"
)
func convertPNG(w io.Writer, png io.Reader) (int64, error) {
p, err := png2prg.New(png2prg.Options{}, png)
if err != nil {
return 0, fmt.Errorf("png2prg.New failed: %w", err)
}
return p.WriteTo(w)
}- Support for even more far-out palette ranges (thanks Perplex).
- Now throws an error if the palette can't be detected properly, this should never happen. Please let me know if you run into this error.
- Separated library and cli tool.
- Library supports the standard io.Reader and io.Writer interfaces.
- Patched TSCrunch further to increase crunch speed and use less memory.
- Added -parallel and -worker flags to treat each input file as standalone and convert all files in parallel. Gifs with multiple frames are still treated as animations.
- Stop relying on .gif filename extension, detect it.
- Add -alt-offset flag to force screenshot offset 32, 36), used by a few graphicians. Though, please switch to the correct 32, 35.
- Add -symbols flag to write symbols to a .sym file.
- Interlace support for mcibitmap (drazlace and truepaint).
- Bugfix: allow blank images input (thanks Spider-J).
- Allow colors not present in the image as -bitpair-colors (thanks Map).
- Added displayer for koala animations.
- Added displayer for hires animations.
- Added -frame-delay flag for animation displayers.
- Added -wait-seconds flag for animation displayers.
- Fixed bug in koala/hires displayers not allowing sids to overlap $c000-$c7ff.
- Expanding wildcards: using pic??.png or pic*.png now also works on Windows.
- Set bank via $dd00 in displayers.
- Added fullscreen fade in/out to koala and hires displayers.
- Added optional .sid support for koala and hires displayers.
- Added optional crunching for all displayers using TSCrunch.
Png2prg was created by Burglar, using the following third-party libraries:
TSCrunch 1.3 by Antonio Savona for optional crunching when exporting an image with a displayer.
Colfade Doc by Veto for the colfade tables used in the koala and hires displayers.
Kick Assembler by Slammer to compile the displayers.
Go by The Go Authors is the programming language used to create png2prg.
-alt-offset
use alternate screenshot offset with x,y = 32,36
-ao
alt-offset
-bitpair-colors string
prefer these colors in 2bit space, eg 0,6,14,3
-bpc string
bitpair-colors
-cpuprofile file
write cpu profile to file
-d display
-d016 int
d016offset (default 1)
-d016offset int
number of pixels to shift with d016 when using interlace (default 1)
-display
include displayer
-force-border-color int
force border color (default -1)
-frame-delay int
frames to wait before displaying next animation frame (default 6)
-h help
-help
help
-i interlace
-interlace
when you supply 2 frames, specify -interlace to treat the images as such
-m string
mode
-memprofile file
write memory profile to file (only in -parallel mode)
-mode string
force graphics mode to koala, hires, mccharset, sccharset, scsprites or mcsprites
-nc
no-crunch
-ng
no-guess
-no-crunch
do not TSCrunch displayer
-no-guess
do not guess preferred bitpair-colors
-no-pack
do not pack chars (only for sc/mc charset)
-np
no-pack
-o string
out
-out string
specify outfile.prg, by default it changes extension to .prg
-p parallel
-parallel
run number of workers in parallel for fast conversion, treat each image as a standalone, not to be used for animations
-q quiet
-quiet
quiet, only display errors
-sid string
include .sid in displayer (see -help for free memory locations)
-sym
symbols
-symbols
export symbols to .sym
-targetdir string
specify targetdir
-td string
targetdir
-v verbose
-verbose
verbose output
-vv
very verbose, show memory usage map in most cases and implies -verbose
-w int
workers (default 12)
-wait-seconds int
seconds to wait before animation starts
-workers int
number of concurrent workers in parallel mode (default 12)