antiX 21 Min IceWM desktop problem

[Member Borg]

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iznit: hmm thats a bit shame. Its weird that there is no FillRect proc to handle that (or its not used).
Its more easy to fill given rect with solid color that manipulate bitmap (memcopy).

Here is very very simple FillRect in 32bit asm.
As you can see, the whole main loop (y_loop) is just 5 instructions.
And not much cache use like in rect to rect copying 😉

For this example, we assume 1024×768 screen size, 32bit color.
DS=ES and points to vid mem already.
No error or out of bound checking of course 😉
Some hacks follows as well 😉

PROC FillRect
; EAX - col, EBX - base vid mem, ECX - (x1,x2), EDX - (y1,y2)
PUSH EDI
PUSH EDX ; +20
PUSH ECX ; +16
PUSH EBX ; +12
PUSH EAX ; +8
MOV EAX,ECX
AND ECX,65535
SHR EAX,16
SUB EAX,ECX
PUSH EAX ; +4 - x pix cnt
PUSH EBP
MOV EBP,ESP
MOV EDI,EBX
MOV ECX,[EBP+16]
AND ECX,65535
SHL ECX,2
ADD EDI,ECX
MOV EAX,EDX
AND EAX,65535
MOV EBX,4096
MUL EBX
MOV ECX,[EBP+4]
SHL ECX,2
SUB EAX,ECX
ADD EDI,EAX
MOV EBX,EAX ;y offset
MOV EDX,[EBP+16]
MOV EAX,EDX
SHR EDX,16
AND EAX,65535
SUB EDX,EAX
MOV EAX,[EBP+8]
y_loop:
MOV ECX,[EBP+4]
REP STOSD ; fill single x-line
ADD EDI,EBX
DEC EDX
JNZ y_loop
POP EBP
POP EAX
POP EAX
POP EBX
POP ECX
POP EDX
POP EDI
RET
ENDP

• This reply was modified 7 months, 2 weeks ago by Borg.
• This reply was modified 7 months, 2 weeks ago by Borg.
• This reply was modified 7 months, 2 weeks ago by Borg.

[Member iznit]

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X.org XFillRectangle exists but is a higher level operation, not the efficent operation you showed. The feh program and others, they would need to first use XCreatePixmap to create a (x*y*C) pixmap before calling XFillRectangle. As for “C” [[[ColorDepth]]], Xorg launches with a fixed color depth. We cannot conserve a significant amount of memory by specifying solidcolor, or even by using the X.org convenience macro ‘BlackPixel‘.

[Member blur13]

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“Even if a 20Mb imagefile is specified, feh exits immediately after handing off the w*h*C sized pixmap to the X display server.”

iznit,

thank you for this! I’ve been optimizing background images for the display resolution thinking less memory would be involved. And I’ve also noticed the “tiling” effect when connecting a laptop to a larger display, now I understand why, and also why “Restart session” solves that.

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