Subversion Repositories Kolibri OS

; pcx.inc

; Copyright (c) 2002 Thomas Mathys

; killer@vantage.ch

;

; This program is free software; you can redistribute it and/or modify

; it under the terms of the GNU General Public License as published by

; the Free Software Foundation; either version 2 of the License, or

; (at your option) any later version.

;

; This program is distributed in the hope that it will be useful,

; but WITHOUT ANY WARRANTY; without even the implied warranty of

; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

; GNU General Public License for more details.

;

; You should have received a copy of the GNU General Public License

; along with this program; if not, write to the Free Software

; Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

%ifndef _PCX_INC

%define _PCX_INC

;**********************************************************

; pcx header

;**********************************************************

PCXHEADER_SIZE	equ	128

struc PCXHEADER

	.id:		resb	1	; id, should be 10

	.version:	resb	1	; pcx version

	.encoding:	resb	1	; 1 = rle

	.bpp:		resb	1	; bits per pixel

	.xmin:		resw	1	; image dimensions

	.ymin:		resw	1

	.xmax:		resw	1

	.ymax:		resw	1

	.hdpi:		resw	1	; horizontal resolution in dpi

	.vdpi:		resw	1	; verttical resolution in dpi

	.colormap:	resb	48	; 16 color palette

	.reserved1:	resb	1

	.nplanes:	resb	1	; # of color planes

	.bytesperline:	resw	1	; # of bytes per scanline. always even

	.palinfo:	resw	1	; 1 = color/bw, 2 = grayscale

	.hscreensize:	resw	1	; horizontal screen size

	.vscreensize:	resw	1	; vertical screen size

	.reserved2:	resb	54

endstruc

section .text

;**********************************************************

; lousy pcx decoder. reads only 8 bit rle packed color images (pcx version 5)

; oh, and yes, currently it can't read images with an odd width.

;

; the routine does not only decode the image data, it converts

; it also to a menuetos putimage compatible format (24 bit, rrggbb)

;

; input		:	esi	address of the pcx file in memory

;			edi	pointer to the memory where the depacked

;				image data should go. (width*height*3 bytes)

;			ebx	file size in bytes

;

; output	:	decoded image in [edi]

;

; destroys	:	nothing

;

;**********************************************************

loadPCX:

	pushad

	pushfd

	; calculate number of pixels to decode.

	; this is actually wrong, because if the image has an odd

	; width, there will be an unused pixel at the end of each

	; scanline.

	movzx eax,word [esi+PCXHEADER.xmax]	; eax = image width

	sub ax,[esi+PCXHEADER.xmin]

	inc eax

	movzx ecx,word [esi+PCXHEADER.ymax]	; ecx = image height

	sub cx,[esi+PCXHEADER.ymin]

	inc ecx

	mul ecx

	mov ebp,eax				; ebp = # of pixels to decode

	; move ebx to beginning of palette and

	; esi to beginning of packed image data

	sub ebx,768

	add ebx,esi

	add esi,PCXHEADER_SIZE

	; decode image data

	xor ecx,ecx				; clear bits 8..31 !

	xor eax,eax				;	"

.decode:

	lodsb					; read byte from input stream

	cmp al,192				; encoded/unencoded byte ?

	jae short .encoded

	lea edx,[eax*2+eax]			; read color values from

	mov al,[ebx+edx+2]			; palette and store them

	stosb					; in the destination image

	mov al,[ebx+edx+1]

	stosb

	mov al,[ebx+edx+0]

	stosb

	dec ebp					; one less to go...

	jmp short .continue

.encoded:

	and al,00111111b			; calc # of times to repeat

	mov cl,al

	lodsb					; read data byte

	lea edx,[eax*2+eax]			; read color values from palette

	mov al,[ebx+edx+2]

	mov ah,[ebx+edx+1]

	mov dl,[ebx+edx+0]

.bla:						; write color values

	stosb

	mov [edi],ah

	inc edi

	mov [edi],dl

	inc edi

	dec ebp					; one less to go...

	loop .bla

	xor ah,ah				; reset ah to 0 !

.continue:

	or ebp,ebp				; all pixels decoded ?

	jnz short .decode

	popfd

	popad

	ret

%endif