adding CI (CommanderX16 Image) file viewer

This commit is contained in:
Irmen de Jong 2020-12-10 00:03:47 +01:00
parent 7549ddcd2b
commit 7a7270d769
2 changed files with 195 additions and 0 deletions

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@ -0,0 +1,185 @@
%target cx16
%import graphics
%import textio
%import diskio
%import c64colors
%zeropage basicsafe
; CommanderX16 Image file format.
; Numbers are encoded in little endian format (lsb first).
;
; offset value
; -----------------
; HEADER (12 bytes):
; 0-1 'CI' in petscii , from "CommanderX16 Image".
; 2 Size of the header data following this byte (always 9, could become more if format changes)
; 3-4 Width in pixels (must be multiple of 8)
; 5-6 Height in pixels
; 7 Bits-per-pixel (1, 2, 4 or 8) (= 2, 4, 16 or 256 colors)
; this also determines the number of palette entries following later.
; 8 Settings bits.
; bit 0 and 1 = compression. 00 = uncompressed
; 01 = PCX-RLE [TODO not yet implemented]
; 10 = LZSA [TODO not yet implemented]
; 11 = Exomizer [TODO not yet implemented]
; bit 2 = palette format. 0 = 4 bits/channel (2 bytes per color, $0R $GB) [TODO not yet implemented]
; 1 = 8 bits/channel (3 bytes per color, $RR $GG $BB)
; 4 bits per channel is the Cx16's native palette format.
; bit 3 = bitmap format. 0 = raw bitmap pixels
; 1 = tile-based image [TODO not yet implemented]
; bit 4 = hscale (horizontal display resulution) 0 = 320 pixels, 1 = 640 pixels
; bit 5 = vscale (vertical display resulution) 0 = 240 pixels, 1 = 480 pixels
; bit 6,7: reserved, set to 0
; 9-11 Size of the bitmap data following the palette data.
; This is a 24-bits number, can be 0 ("unknown", in which case just read until the end).
;
; PALETTE (always present but size varies):
; 12-... Color palette. Number of entries = 2 ^ bits-per-pixel. Number of bytes per
; entry is 2 or 3, depending on the chosen palette format in the setting bits.
;
; BITMAPDATA (size varies):
; After this, the actual image data follows.
; If the bitmap format is 'raw bitmap pixels', the bimap is simply written as a sequence
; of bytes making up the image's scan lines. #bytes per scan line = width * bits-per-pixel / 8
; If it is 'tiles', .... [TODO]
; If a compression scheme is used, the bitmap data here has to be decompressed first.
main {
ubyte[256] buffer
ubyte[256] buffer2
ubyte[256] buffer3
str filename = "trsi256.ci"
sub start() {
buffer[0] = 0
buffer2[0] = 0
buffer3[0] = 0
ubyte read_success = false
if(io.f_open(8, filename)) {
uword size = io.f_read(buffer, 12) ; read the header
if size==12 {
if buffer[0]=='c' and buffer[1]=='i' and buffer[2] == 9 {
if buffer[11] {
txt.print("file too large >64kb!\n") ; TODO add support for large files
} else {
uword width = mkword(buffer[4], buffer[3])
uword height = mkword(buffer[6], buffer[5])
ubyte bpp = buffer[7]
uword num_colors = 1
num_colors <<= bpp ; TODO FIX THIS: uword num_colors = 1 << bpp
ubyte flags = buffer[8]
ubyte compression = flags & %00000011
ubyte palette_format = (flags & %00000100) >> 2
ubyte bitmap_format = (flags & %00001000) >> 3
ubyte hscale = (flags & %00010000) >> 4
ubyte vscale = (flags & %00100000) >> 5
uword bitmap_size = mkword(buffer[10], buffer[9])
uword palette_size
if palette_format
palette_size = 3*num_colors
else
palette_size = 2*num_colors
txt.print(filename)
txt.print("\ndimensions: ")
txt.print_uw(width)
txt.chrout('*')
txt.print_uw(height)
txt.print("\nbits-per-pixel: ")
txt.print_ub(bpp)
txt.print(" #colors: ")
txt.print_uw(num_colors)
txt.print("\ncompression: ")
txt.print_ub(compression)
txt.print("\npalette format: ")
txt.print_ub(palette_format)
txt.print("\nbitmap format: ")
txt.print_ub(bitmap_format)
txt.print("\nscaling: ")
txt.print_ub(hscale)
txt.chrout(',')
txt.print_ub(vscale)
txt.chrout('\n')
if compression!=0 {
txt.print("compression not yet supported\n") ; TODO implement this
} else if bitmap_format==1 {
txt.print("tiled bitmap not yet supported\n") ; TODO implement this
} else {
txt.print("reading palette and bitmap...\n")
size = io.f_read(buffer, palette_size)
if size==palette_size {
size = io.f_read($3000, bitmap_size)
read_success = size==bitmap_size
}
}
}
}
} else {
txt.print("io error or invalid image file\n")
}
io.f_close()
if read_success {
txt.print("done!\n")
} else {
txt.print("error loading image file.\n")
}
}
txt.print(diskio.status(8))
}
}
io {
ubyte iteration_in_progress = false
sub f_open(ubyte drivenumber, uword filenameptr) -> ubyte {
f_close()
c64.SETNAM(strlen(filenameptr), filenameptr)
c64.SETLFS(11, drivenumber, 0)
void c64.OPEN() ; open 11,8,0,"filename"
if_cc {
iteration_in_progress = true
void c64.CHKIN(11) ; use #2 as input channel
if_cc
return true
}
f_close()
return false
}
sub f_read(uword bufferpointer, uword buffersize) -> uword {
if not iteration_in_progress
return 0
uword actual = 0
repeat buffersize {
ubyte data = c64.CHRIN()
@(bufferpointer) = data
bufferpointer++
actual++
ubyte status = c64.READST()
if status==64
f_close() ; end of file, close it
if status
return actual
}
return actual
}
sub f_close() {
; -- end an iterative file loading session (close channels).
if iteration_in_progress {
c64.CLRCHN()
c64.CLOSE(11)
iteration_in_progress = false
}
}
}

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@ -7,6 +7,16 @@
main { main {
sub start() { sub start() {
ubyte error
error = error and error!=64 ; TODO fix crash (also for other datatypes)
ubyte bpp = buffer[7]
uword num_colors = 1 << bpp ; TODO FIX THIS
ubyte[] barr = [0,0,0] ubyte[] barr = [0,0,0]
uword[] warr = [0,0,0] uword[] warr = [0,0,0]