assembly - How to read image file and display on screen in windows tasm dosbox -
im learning graphical programming in tasm using dosbox. ive been using bunch of loops draw square blocks of pixels , hard. want know if theres way read image , display it. know how read txt file maybe start. pls help
you need write/use image loader or use own image file format. bmp may simple has in compression pixel formats etc still can focus on specific type of bmp , ignore others...
back in days of ms-dos using 256 color pcx images palette used 256 color video modes. here nasm linez game example:
see pcx: subroutine. decodes loaded pcx file memory ds:0 raw vga image @ es:di. beware support 64 kbyte size limit !!! visualize image have copy es:di content videoram (assuming a000:0000) example rep movsd or can set es:di in first place (but flicker).
this pcx loader not use palette image need encode ... (the routines change vga palette included in source need extract rgb values pcx think @ end of file) here:
if converts pcx 32bit raw image.
for more info ms-dos game programing see pcgpe 1.0
here game example (tasm) uses own image file-format:
it has text menues, binary file access, 320x200 sprite graphics, 3 human players
[edit1] new code
i removed old code example , instead created compilable , working 8bit pcx color palette viewer in tasm. uses vesa 800x600x256 colors mode (103h).
the image must fit screen , file size must less 64 kbyte !!!
i did not add checks or error messages ... loads file image.pcx , displays on vesa wait on key hit end exit. here tasm source:
pcx.asm
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; .386 ideal model tiny ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; dataseg file: db 'image.pcx',0 ;filename load buff: ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; codeseg startupcode scrxs equ 800 scrys equ 600 mov ax,103h ; vesa 800x600x256 call vesamod mov al,0 call vesapag ; scrxs equ 320 ; scrys equ 200 ; mov ax,19 ; vga 320x200x256 ; int 10h lea dx,[file] ; load pcx ds:buff, cx bytes call fopen lea dx,[buff] mov cx,64000 ; max value fit ds segment call fread ; cx pcx real size call fclose lea si,[buff] ; decode directly vram mov ax,0a000h mov es,ax mov di,0 call pcx mainl0: mov ax,256 ; test keyboard int 16h jz mainl0 sub ax,ax ; clear key buffer int 16h mov ax,3 ;|vga 80x25 text int 16 ret ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; vesamod:pusha ;set vesa videomode ax mov bx,ax mov ax,4f02h int 16 popa ret ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; vesapag:pusha ;al=page switch vesa video page window mov [cs:scrpag],al mov dl,al sub dh,dh sub bx,bx mov ax,4f05h ; window int 16 popa ret ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; .386p scrpag db 0 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; .386p hand dw 0 ;### handler... ferr db 0 ;### dos error code ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; fopen: pusha ;ds:dx = file name, [hand] <= file handle mov ax,3d02h int 21h mov bl,0 jnc fopen0 mov bl,al sub ax,ax fopen0: mov [cs:hand],ax mov [cs:ferr],bl popa ret ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; fclose: pusha ;[hand] = file handle mov bx,[cs:hand] mov ah,3eh int 21h mov bl,0 jnc fclose0 mov bl,al sub ax,ax fclose0:mov [cs:ferr],bl mov [cs:hand],ax popa ret ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; fread: pusha ;ds:dx = adr, cx = lenght, [hand] = hand, cx => read mov bx,[cs:hand] mov ah,3fh int 21h mov bl,0 jnc fread0 mov bl,al sub ax,ax fread0: mov [cs:ferr],bl mov [cs:freadsz],ax popa mov cx,[cs:freadsz] ret freadsz dw 0 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; pcx: pusha ;decode pcx @ ds:si es:di cx = pcx size push ds push es push ecx push edx push si ;set palette add si,cx sub si,768 sub ax,ax pall0: mov dx,3c8h mov al,ah out dx,al inc dx lodsb shr al,2 out dx,al lodsb shr al,2 out dx,al lodsb shr al,2 out dx,al inc ah jnz pall0 pop si mov ax,[ds:si+8] ;get xs sub ax,[ds:si+4] inc ax mov [cs:pcxxs],ax mov [cs:pcxx],ax mov ax,[ds:si+10] ;get ys sub ax,[ds:si+6] inc ax mov [cs:pcxys],ax mul [cs:pcxxs] push dx push ax pop edx add si,128 ;src start after pcx header sub ecx,ecx ;rle decoder of pcx pcxl0: lodsb mov cx,1 cmp al,192 jb pcxr0 mov cl,al , cl,63 lodsb pcxr0: mov bx,cx pcxl1: call point dec [cs:pcxx] ;correct next screen line position if end of pcx line jnz pcxr1 mov ax,[cs:pcxxs] mov [cs:pcxx],ax neg ax add ax,scrxs add di,ax jnc pcxr1 ; page swith mov al,[cs:scrpag] inc al call vesapag pcxr1: loop pcxl1 mov cx,bx sub edx,ecx jz pcxesc jnc pcxl0 pcxesc: pop edx pop ecx pop es pop ds popa ret pcxxs dw 0 ;pcx resolution pcxys dw 0 pcxx dw 0 ;actual x coordinate ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; point: mov [es:di],al ;point ;estosb inc di jnz pntesc ; page swith mov al,[cs:scrpag] inc al call vesapag pntesc: ret ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; so take image 800x600 convert 256 color pcx palette , rename image.pcx. place *.com file , run. compiled volcov commander extension script vc.ext this:
asm:@c:\language\compil\tasm\tasm !.! /ic:\language\source\tasm\inc @c:\language\compil\tasm\tlink !.obj /t /x @del !.obj so each time hit enter on asm file compile. change paths , if not targeting *.com files change /t switch accordingly. here preview dosbox:
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