prog8/examples/cx16/imageviewer/pcx_module.p8
2021-01-13 22:11:51 +01:00

171 lines
5.5 KiB
Lua

%target cx16
%import gfx2
%import textio
%import diskio
pcx_module {
sub show_image(uword filenameptr) -> ubyte {
ubyte load_ok = false
if diskio.f_open(8, filenameptr) {
ubyte[128] header
uword size = diskio.f_read(header, 128)
if size==128 {
if header[0] == $0a and header[2] == 1 {
ubyte bits_per_pixel = header[3]
if bits_per_pixel==1 or bits_per_pixel==4 or bits_per_pixel==8 {
uword width = mkword(header[$09], header[$08]) - mkword(header[$05], header[$04]) + 1
uword height = mkword(header[$0b], header[$0a]) - mkword(header[$07], header[$06]) + 1
ubyte number_of_planes = header[$41]
uword palette_format = mkword(header[$45], header[$44])
uword num_colors = 2**bits_per_pixel
if number_of_planes == 1 {
if (width & 7) == 0 {
gfx2.clear_screen()
if palette_format==2
custompalette.set_grayscale256()
else if num_colors == 16
palette.set_rgb8(&header + $10, 16)
else if num_colors == 2
palette.set_monochrome()
when bits_per_pixel {
8 -> load_ok = bitmap.do8bpp(width, height)
4 -> load_ok = bitmap.do4bpp(width, height)
1 -> load_ok = bitmap.do1bpp(width, height)
}
if load_ok {
load_ok = c64.CHRIN()
if load_ok == 12 {
; there is 256 colors of palette data at the end
uword palette_mem = sys.progend()
load_ok = false
size = diskio.f_read(palette_mem, 3*256)
if size==3*256 {
load_ok = true
palette.set_rgb8(palette_mem, num_colors)
}
}
}
} else
txt.print("width not multiple of 8!\n")
} else
txt.print("has >256 colors!\n")
}
}
}
diskio.f_close()
}
return load_ok
}
}
bitmap {
uword offsetx
uword offsety
uword py
uword px
ubyte y_ok
ubyte status
sub start_plot(uword width, uword height) {
offsetx = 0
offsety = 0
y_ok = true
py = 0
px = 0
if width < gfx2.width
offsetx = (gfx2.width - width) / 2
if height < gfx2.height
offsety = (gfx2.height - height) / 2
status = (not c64.READST()) or (c64.READST()&64==64)
}
sub next_scanline() {
px = 0
py++
y_ok = py < gfx2.height
gfx2.position(offsetx, offsety+py)
status = (not c64.READST()) or (c64.READST()&64==64)
}
sub do1bpp(uword width, uword height) -> ubyte {
start_plot(width, height)
gfx2.position(offsetx, offsety)
while py < height and status {
ubyte b = c64.CHRIN()
if b>>6==3 {
b &= %00111111
ubyte dat = c64.CHRIN()
repeat b {
if y_ok
gfx2.set_8_pixels_from_bits(dat, 1, 0)
px += 8
}
} else {
if y_ok
gfx2.set_8_pixels_from_bits(b, 1, 0)
px += 8
}
if px==width
next_scanline()
}
return status
}
sub do4bpp(uword width, uword height) -> ubyte {
start_plot(width, height)
gfx2.position(offsetx, offsety)
while py < height and status {
ubyte b = c64.CHRIN()
if b>>6==3 {
b &= %00111111
ubyte dat = c64.CHRIN()
if y_ok
repeat b {
gfx2.next_pixel(dat>>4)
gfx2.next_pixel(dat & 15)
}
px += b*2
} else {
if y_ok {
gfx2.next_pixel(b>>4)
gfx2.next_pixel(b & 15)
}
px += 2
}
if px==width
next_scanline()
}
return status
}
sub do8bpp(uword width, uword height) -> ubyte {
start_plot(width, height)
gfx2.position(offsetx, offsety)
while py < height and status {
ubyte b = c64.CHRIN()
if b>>6==3 {
b &= %00111111
ubyte dat = c64.CHRIN()
if y_ok
repeat b
gfx2.next_pixel(dat)
px += b
} else {
if y_ok
gfx2.next_pixel(b)
px++
}
if px==width
next_scanline()
}
return status
}
}