Index
> OS Construction > vesa graphics-fonts |
| Author |
|
|
Dex4u 16 Oct 2007, 18:05
I will give you a basic demo of how it work, its up to you to make it into a working function.
Code: mov esi,Stop ;point to the fonts call DrawImage ; call the function jmp $;***********************************; Draws text.;***********************************DrawImage: mov edi,[ModeInfo_PhysBasePtr] ;move the screen address into edi add edi,0 ; you can add a screen offset here, just the top left hand corner for this demo xor edx,edx ; zero edx mov dl,7 ; move the font high in here. cldGetData: lodsd ; load the top row of "STOP" into EAX MOV ebx,eax ;mov it in EBX MOV CL,32 ;move the number of bits to test.CheckBit: test ebx,80000000h ; here we test the bit for a 0 or 1 JZ ZeroBit ; if 0 jump to ZeroBit label xor eax,eax ; if 1 put a black pixel stosd jmp SkipZeroBit: add edi,4 ; just move the pointer on by 4 (eg size of a pixel)Skip: shl ebx,1 ; move ebx along to test the next bit loop CheckBit ;loop again if cx not 0 add edi,800*4-32*4 ;add screen X - width of "STOP" dec edx jnz GetData ;if not 0 loop retStop:db 78h,38h,7ch,38hdb 44h,44h,10h,44hdb 44h,44h,10h,40hdb 78h,44h,10h,38hdb 40h,44h,10h,04hdb 40h,44h,10h,44hdb 40h,38h,10h,38h Now this is just a demo, you would normaly use single fonts, set in a font list. So let for example do a basic 0 font 0xxx0 = 0xe x000x = 0x11 x000x = 0x11 0xxx0 = 0xe You would test each bit if it was a 0 you just move the pointer on one pixel, it its a 1 (but in this case x) you would put a pixel. |
|||
16 Oct 2007, 18:05 |
|
|
dosin 17 Oct 2007, 03:59
Dex4u, I noticed your stop is spelled right to left? POTS
Also: If I were to draw just an A.. I would have to change the mov cl,32 to mov cl,8 since there is just eight bytes across.. (00000000)*1 mov dl,7 would stay the same add edi,800*4-32*4 ? add edi, screen_width*number_of_text? - total_bits_across?*number_of_text? and last would the color be in the format of RGB? mov eax,0x00FFFFFF Code: A: db 38h,44h,44h,7ch,44h,44h,44h I've been away from my computer and have not been able to try it... I am just trying to understand it....Maybe I need some rest-- lol Thanks - again dex4u!!! |
|||
|
17 Oct 2007, 03:59 |
|
|
Dex4u 17 Oct 2007, 06:45
Yes you have under stud the code right
 .
Code: mov esi,LetterA ;point to the fonts call DrawImage ; call the function jmp $;***********************************; Draws text.;***********************************DrawImage: mov edi,[ModeInfo_PhysBasePtr] ;move the screen address into edi add edi,0 ; you can add a screen offset here, just the top left hand corner for this demo xor edx,edx ; zero edx mov dl,7 ; move the font high in here. cldGetData: lodsb ; CHANGE THIS TO LODSB MOV BL,AL ; CHANGE THIS TO BL,AL MOV CL,8 ;CHANGE THIS TO 8.CheckBit: test BL,80h ; CHANGE THIS TO BL AND 80H JZ ZeroBit ; if 0 jump to ZeroBit label xor eax,eax ; if 1 put a black pixel stosd jmp SkipZeroBit: add edi,4 ; just move the pointer on by 4 (eg size of a pixel)Skip: shl bl,1 ; CHANGE THIS TO BL loop CheckBit ;loop again if cx not 0 add edi,800*4-8*4 ;CHANGE THIS TO 800*4-8*4 as we are only puting 1 letter dec edx jnz GetData ;if not 0 loop retLetterA: db 38h,44h,44h,7ch,44h,44h,44h The above code should work for on letter, but is untested. Note: these fonts are 8x7, but if you were to use 8x16 you would need to mod things. As for color yes, but you have to be carefull, as some card use 24bits and others 32bits, so some are 00RGB and some are RGB, most are 00RGB. You need to test in the code for BPP eg: Code: PutFont:cmp [ModeInfo_BitsPerPixel],24je Its24BPP;do the function for 32 bits herejmp LetsGoIts24BPP:;do the function for 24 bits hereLetsGo: ret Good luck. |
|||
|
17 Oct 2007, 06:45 |
|
|
dosin 17 Oct 2007, 10:48
Thanks, for confirming that ... by the way I checked out your website Dex4u- pretty cool!!! Are you going to add multi-tasking latter on?
so, to posistion the text I would: add edi,Txt_X*4+640*4*Txt_Y All sorry but one more question... In a text file like with note pad is all the text stored as hex data..? then once read from a file it is converted from B hex = B font to screen ? |
|||
|
17 Oct 2007, 10:48 |
|
|
edfed 17 Oct 2007, 13:57
no 0bh is not the code for 'b' ascii
'b' is 42h hexadecimal is only an interpretation of a binary value ascii is an other hex is natural, ascii is normative to put a letter on a screen you need some datas x,y resolution x,y position a byte that represent the ascii letter and a table were is the font all letters in the font are table too you have vectorial font fixed font variable font so when you write a letter on the screen you only put an image of the letter loaded in the font table, at x,y position and it is the same for all modes, text and graphic in text mode, you don't need to load the font, it is automatic in all graphics modes you need!!! simple no???? |
|||
|
17 Oct 2007, 13:57 |
|
|
Dex4u 18 Oct 2007, 01:09
dosin wrote: Thanks, for confirming that ... by the way I checked out your website Dex4u- pretty cool!!! Are you going to add multi-tasking latter on? Thanks dosin, DexOS is at its hart a single-tasking OS, but it already as a demo to do multi-threading and it can load reloctable files, so it would not be too hard to make a MT ver. To Help you fully understand how to print in vesa 800x600 mode, i have written you a simple demo, i will send you a link in a PM. Good luck. |
|||
|
18 Oct 2007, 01:09 |
|
|
dosin 18 Oct 2007, 05:26
Thanks, Dex!!!!
I did get it working.. and the example was great!!! This will help me see how the fonts work and for creating new ones!!! I have added a screen shot from qemu of the text_graphics!
|
|||||||||||
|
18 Oct 2007, 05:26 |
|
|
Dex4u 18 Oct 2007, 20:06
Cool it looks great.
|
|||
|
18 Oct 2007, 20:06 |
|
< Last Thread | Next Thread > |
Forum Rules:
|