Draw a pixel
You are encouraged to solve this task according to the task description, using any language you may know.
- Task
Create a window and draw a pixel in it, subject to the following:
- the window is 320 x 240
- the color of the pixel must be red (255,0,0)
- the position of the pixel is x = 100, y = 100
Action!
The solution of this task is tricky because of technical limitation of Atari 8-bit computer. The computer supports high resolution graphics mode of 320 pixels width, 192 pixels height and 1 bit per pixel color. The color of the pixel cannot be set independently from the background color and only different luminance can be specified. To draw a red pixel the background must be set to light-red color. <lang Action!>PROC Main()
BYTE CH=$02FC, ;Internal hardware value for last key pressed PALNTSC=$D014 ;To check if PAL or NTSC system is used
Graphics(8+16) ;Graphics 320x192 with 2 luminances IF PALNTSC=15 THEN SetColor(1,4,6) ;Red color for NTSC SetColor(2,4,15) ELSE SetColor(1,2,6) ;Red color for PAL SetColor(2,2,15) FI Color=1 Plot(100,100) DO UNTIL CH#$FF OD CH=$FF
RETURN</lang>
- Output:
Screenshot from Atari 8-bit computer
Ada
<lang Ada>with SDL.Video.Windows.Makers; with SDL.Video.Renderers.Makers; with SDL.Events.Events;
procedure Draw_A_Pixel is
Width : constant := 320; Height : constant := 200;
Window : SDL.Video.Windows.Window; Renderer : SDL.Video.Renderers.Renderer;
procedure Wait is
use type SDL.Events.Event_Types;
Event : SDL.Events.Events.Events;
begin
loop
while SDL.Events.Events.Poll (Event) loop
if Event.Common.Event_Type = SDL.Events.Quit then
return;
end if;
end loop;
delay 0.100;
end loop;
end Wait;
begin
if not SDL.Initialise (Flags => SDL.Enable_Screen) then
return;
end if;
SDL.Video.Windows.Makers.Create (Win => Window,
Title => "Draw a pixel",
Position => SDL.Natural_Coordinates'(X => 10, Y => 10),
Size => SDL.Positive_Sizes'(Width, Height),
Flags => 0);
SDL.Video.Renderers.Makers.Create (Renderer, Window.Get_Surface);
Renderer.Set_Draw_Colour ((0, 0, 0, 255));
Renderer.Fill (Rectangle => (0, 0, Width, Height));
Renderer.Set_Draw_Colour ((255, 0, 0, 255));
Renderer.Draw (Point => (100, 100));
Window.Update_Surface;
Wait; Window.Finalize; SDL.Finalise;
end Draw_A_Pixel;</lang>
ARM Assembly
<lang ARM Assembly>
/* ARM assembly Raspberry PI */ /* program dpixel.s */
/* compile with as */ /* link with gcc and options -lX11 -L/usr/lpp/X11/lib */
/********************************************/ /*Constantes */ /********************************************/ .equ STDOUT, 1 @ Linux output console .equ EXIT, 1 @ Linux syscall .equ WRITE, 4 @ Linux syscall /* constantes X11 */ .equ KeyPressed, 2 .equ ButtonPress, 4 .equ MotionNotify, 6 .equ EnterNotify, 7 .equ LeaveNotify, 8 .equ Expose, 12 .equ ClientMessage, 33 .equ KeyPressMask, 1 .equ ButtonPressMask, 4 .equ ButtonReleaseMask, 8 .equ ExposureMask, 1<<15 .equ StructureNotifyMask, 1<<17 .equ EnterWindowMask, 1<<4 .equ LeaveWindowMask, 1<<5 .equ ConfigureNotify, 22
/*******************************************/
/* DONNEES INITIALISEES */
/*******************************************/
.data
szWindowName: .asciz "Windows Raspberry"
szRetourligne: .asciz "\n"
szMessDebutPgm: .asciz "Program start. \n"
szMessErreur: .asciz "Server X not found.\n"
szMessErrfen: .asciz "Can not create window.\n"
szMessErreurX11: .asciz "Error call function X11. \n"
szMessErrGc: .asciz "Can not create graphics context.\n"
szTitreFenRed: .asciz "Pi"
szTexte1: .asciz "<- red pixel is here !!"
.equ LGTEXTE1, . - szTexte1
szTexte2: .asciz "Press q for close window or clic X in system menu."
.equ LGTEXTE2, . - szTexte2
szLibDW: .asciz "WM_DELETE_WINDOW" @ special label for correct close error
/*************************************************/ szMessErr: .ascii "Error code hexa : " sHexa: .space 9,' '
.ascii " decimal : "
sDeci: .space 15,' '
.asciz "\n"
/*******************************************/ /* DONNEES NON INITIALISEES */ /*******************************************/ .bss .align 4 ptDisplay: .skip 4 @ pointer display ptEcranDef: .skip 4 @ pointer screen default ptFenetre: .skip 4 @ pointer window ptGC: .skip 4 @ pointer graphic context ptGC1: .skip 4 @ pointer graphic context1 key: .skip 4 @ key code wmDeleteMessage: .skip 8 @ ident close message event: .skip 400 @ TODO event size ?? PrpNomFenetre: .skip 100 @ window name proprety buffer: .skip 500 iWhite: .skip 4 @ rgb code for white pixel iBlack: .skip 4 @ rgb code for black pixel /**********************************************/ /* -- Code section */ /**********************************************/ .text .global main
main: @ entry of program
ldr r0,iAdrszMessDebutPgm @
bl affichageMess @ display start message on console linux
/* attention r6 pointer display*/
/* attention r8 pointer graphic context */
/* attention r9 ident window */
/*****************************/
/* OPEN SERVER X11 */
/*****************************/
mov r0,#0
bl XOpenDisplay @ open X server
cmp r0,#0 @ error ?
beq erreurServeur
ldr r1,iAdrptDisplay
str r0,[r1] @ store display address
mov r6,r0 @ and in register r6
ldr r2,[r0,#+132] @ load default_screen
ldr r1,iAdrptEcranDef
str r2,[r1] @ store default_screen
mov r2,r0
ldr r0,[r2,#+140] @ load pointer screen list
ldr r5,[r0,#+52] @ load value white pixel
ldr r4,iAdrWhite @ and store in memory
str r5,[r4]
ldr r3,[r0,#+56] @ load value black pixel
ldr r4,iAdrBlack @ and store in memory
str r3,[r4]
ldr r4,[r0,#+28] @ load bits par pixel
ldr r1,[r0,#+8] @ load root windows
/**************************/
/* CREATE WINDOW */
/**************************/
mov r0,r6 @ address display
mov r2,#0 @ window position X
mov r3,#0 @ window position Y
mov r8,#0 @ for stack alignement
push {r8}
push {r3} @ background = black pixel
push {r5} @ border = white pixel
mov r8,#2 @ border size
push {r8}
mov r8,#240 @ hauteur
push {r8}
mov r8,#320 @ largeur
push {r8}
bl XCreateSimpleWindow
add sp,#24 @ stack alignement 6 push (4 bytes * 6)
cmp r0,#0 @ error ?
beq erreurF
ldr r1,iAdrptFenetre
str r0,[r1] @ store window address in memory
mov r9,r0 @ and in register r9
/*****************************/
/* add window property */
/*****************************/
mov r0,r6 @ display address
mov r1,r9 @ window address
ldr r2,iAdrszWindowName @ window name
ldr r3,iAdrszTitreFenRed @ window name reduced
mov r4,#0
push {r4} @ parameters not use
push {r4}
push {r4}
push {r4}
bl XSetStandardProperties
add sp,sp,#16 @ stack alignement for 4 push
/**************************************/
/* for correction window close error */
/**************************************/
mov r0,r6 @ display address
ldr r1,iAdrszLibDW @ atom address
mov r2,#1 @ False créate atom if not exists
bl XInternAtom
cmp r0,#0 @ error X11 ?
ble erreurX11
ldr r1,iAdrwmDeleteMessage @ recept address
str r0,[r1]
mov r2,r1 @ return address
mov r0,r6 @ display address
mov r1,r9 @ window address
mov r3,#1 @ number of protocols
bl XSetWMProtocols
cmp r0,#0 @ error X11 ?
ble erreurX11
/**********************************/
/* create graphic context */
/**********************************/
mov r0,r6 @ display address
mov r1,r9 @ window address
mov r2,#0 @ not use for simply context
mov r3,#0
bl XCreateGC
cmp r0,#0 @ error ?
beq erreurGC
ldr r1,iAdrptGC
str r0,[r1] @ store address graphic context
mov r8,r0 @ and in r8
@ create other GC
mov r0,r6 @ display address
mov r1,r9 @ window address
mov r2,#0 @ not use for simply context
mov r3,#0
bl XCreateGC
cmp r0,#0 @ error ?
beq erreurGC
ldr r1,iAdrptGC1
str r0,[r1] @ store address graphic context 1
mov r1,r0
mov r0,r6
mov r2,#0xFF0000 @ color red
bl XSetForeground
cmp r0,#0
beq erreurGC
/****************************/
/* modif window background */
/****************************/
mov r0,r6 @ display address
mov r1,r9 @ window address
ldr r2,iGris1 @ background color
bl XSetWindowBackground
cmp r0,#0 @ error ?
ble erreurX11
/***************************/
/* OUF!! window display */
/***************************/
mov r0,r6 @ display address
mov r1,r9 @ window address
bl XMapWindow
/****************************/
/* Write text1 in the window */
/****************************/
mov r0,r6 @ display address
mov r1,r9 @ window address
mov r2,r8 @ address graphic context
mov r3,#105 @ position x
sub sp,#4 @ stack alignement
mov r4,#LGTEXTE1 - 1 @ size string
push {r4} @ on the stack
ldr r4,iAdrszTexte1 @ string address
push {r4}
mov r4,#105 @ position y
push {r4}
bl XDrawString
add sp,sp,#16 @ stack alignement 3 push and 1 stack alignement
cmp r0,#0 @ error ?
blt erreurX11
/****************************/
/* Write text2 in the window */
/****************************/
mov r0,r6 @ display address
mov r1,r9 @ window address
mov r2,r8 @ address graphic context
mov r3,#10 @ position x
sub sp,#4 @ stack alignement
mov r4,#LGTEXTE2 - 1 @ size string
push {r4} @ on the stack
ldr r4,iAdrszTexte2 @ string address
push {r4}
mov r4,#200 @ position y
push {r4}
bl XDrawString
add sp,sp,#16 @ stack alignement 3 push and 1 stack alignement
cmp r0,#0 @ error ?
blt erreurX11
/****************************************/
/* draw pixel */
/****************************************/
mov r0,r6 @ display address
mov r1,r9 @ window address
ldr r2,iAdrptGC1
ldr r2,[r2] @ address graphic context 1
mov r3,#100 @ position x
sub sp,sp,#4 @ stack alignement
mov r4,#100 @ position y
push {r4} @ on the stack
bl XDrawPoint
add sp,sp,#8 @ stack alignement 1 push and 1 stack alignement
cmp r0,#0 @ error ? blt erreurX11 /****************************/ /* Autorisations */ /****************************/ mov r0,r6 @ display address mov r1,r9 @ window address ldr r2,iFenetreMask @ autorisation mask bl XSelectInput cmp r0,#0 @ error ? ble erreurX11 /****************************/ /* Events loop */ /****************************/
1:
mov r0,r6 @ display address
ldr r1,iAdrevent @ events address
bl XNextEvent @ event ?
ldr r0,iAdrevent
ldr r0,[r0] @ code event
cmp r0,#KeyPressed @ key ?
bne 2f
ldr r0,iAdrevent @ yes read key in buffer
ldr r1,iAdrbuffer
mov r2,#255
ldr r3,iAdrkey
mov r4,#0
push {r4} @ stack alignement
push {r4}
bl XLookupString
add sp,#8 @ stack alignement 2 push
cmp r0,#1 @ is character key ?
bne 2f
ldr r0,iAdrbuffer @ yes -> load first buffer character
ldrb r0,[r0]
cmp r0,#0x71 @ character q for quit
beq 5f @ yes -> end
b 4f
2:
/* */ /* for example clic mouse button */ /************************************/ cmp r0,#ButtonPress @ clic mouse buton bne 3f ldr r0,iAdrevent ldr r1,[r0,#+32] @ position X mouse clic ldr r2,[r0,#+36] @ position Y @ etc for eventuel use b 4f
3:
cmp r0,#ClientMessage @ code for close window within error bne 4f ldr r0,iAdrevent ldr r1,[r0,#+28] @ code message address ldr r2,iAdrwmDeleteMessage @ equal code window créate ??? ldr r2,[r2] cmp r1,r2 beq 5f @ yes -> end window
4: @ loop for other event
b 1b /***********************************/ /* Close window -> free ressources */ /***********************************/
5:
mov r0,r6 @ display address ldr r1,iAdrptGC ldr r1,[r1] @ load context graphic address bl XFreeGC cmp r0,#0 blt erreurX11 mov r0,r6 @ display address mov r1,r9 @ window address bl XDestroyWindow cmp r0,#0 blt erreurX11 mov r0,r6 @ display address bl XCloseDisplay cmp r0,#0 blt erreurX11 mov r0,#0 @ return code OK b 100f
erreurF: @ create error window but possible not necessary. Display error by server
ldr r1,iAdrszMessErrfen bl displayError mov r0,#1 @ return error code b 100f
erreurGC: @ error create graphic context
ldr r1,iAdrszMessErrGc bl displayError mov r0,#1 b 100f
erreurX11: @ erreur X11
ldr r1,iAdrszMessErreurX11 bl displayError mov r0,#1 b 100f
erreurServeur: @ error no found X11 server see doc putty and Xming
ldr r1,iAdrszMessErreur bl displayError mov r0,#1 b 100f
100: @ standard end of the program
mov r7, #EXIT svc 0
iFenetreMask: .int KeyPressMask|ButtonPressMask|StructureNotifyMask iGris1: .int 0xFFA0A0A0 iAdrWhite: .int iWhite iAdrBlack: .int iBlack iAdrptDisplay: .int ptDisplay iAdrptEcranDef: .int ptEcranDef iAdrptFenetre: .int ptFenetre iAdrptGC: .int ptGC iAdrptGC1: .int ptGC1 iAdrevent: .int event iAdrbuffer: .int buffer iAdrkey: .int key iAdrszLibDW: .int szLibDW iAdrszMessDebutPgm: .int szMessDebutPgm iAdrszMessErreurX11: .int szMessErreurX11 iAdrszMessErrGc: .int szMessErrGc iAdrszMessErreur: .int szMessErreur iAdrszMessErrfen: .int szMessErrfen iAdrszWindowName: .int szWindowName iAdrszTitreFenRed: .int szTitreFenRed iAdrszTexte1: .int szTexte1 iAdrszTexte2: .int szTexte2 iAdrPrpNomFenetre: .int PrpNomFenetre iAdrwmDeleteMessage: .int wmDeleteMessage
/******************************************************************/ /* display text with size calculation */ /******************************************************************/ /* r0 contains the address of the message */ affichageMess:
push {r0,r1,r2,r7,lr} @ save registres
mov r2,#0 @ counter length
1: @ loop length calculation
ldrb r1,[r0,r2] @ read octet start position + index
cmp r1,#0 @ if 0 its over
addne r2,r2,#1 @ else add 1 in the length
bne 1b @ and loop
@ so here r2 contains the length of the message
mov r1,r0 @ address message in r1
mov r0,#STDOUT @ code to write to the standard output Linux
mov r7, #WRITE @ code call system "write"
svc #0 @ call systeme
pop {r0,r1,r2,r7,lr} @ restaur registers
bx lr @ return
/***************************************************/ /* display error message */ /***************************************************/ /* r0 contains error code r1 : message address */ displayError:
push {r0-r2,lr} @ save registers
mov r2,r0 @ save error code
mov r0,r1
bl affichageMess
mov r0,r2 @ error code
ldr r1,iAdrsHexa
bl conversion16 @ conversion hexa
mov r0,r2 @ error code
ldr r1,iAdrsDeci @ result address
bl conversion10 @ conversion decimale
ldr r0,iAdrszMessErr @ display error message
bl affichageMess
100:
pop {r0-r2,lr} @ restaur registers
bx lr @ return
iAdrszMessErr: .int szMessErr iAdrsHexa: .int sHexa iAdrsDeci: .int sDeci /******************************************************************/ /* Converting a register to hexadecimal */ /******************************************************************/ /* r0 contains value and r1 address area */ conversion16:
push {r1-r4,lr} @ save registers
mov r2,#28 @ start bit position
mov r4,#0xF0000000 @ mask
mov r3,r0 @ save entry value
1: @ start loop
and r0,r3,r4 @value register and mask lsr r0,r2 @ move right cmp r0,#10 @ compare value addlt r0,#48 @ <10 ->digit addge r0,#55 @ >10 ->letter A-F strb r0,[r1],#1 @ store digit on area and + 1 in area address lsr r4,#4 @ shift mask 4 positions subs r2,#4 @ counter bits - 4 <= zero ? bge 1b @ no -> loop
100:
pop {r1-r4,lr} @ restaur registers
bx lr @return
/******************************************************************/ /* Converting a register to a decimal unsigned */ /******************************************************************/ /* r0 contains value and r1 address area */ /* r0 return size of result (no zero final in area) */ /* area size => 11 bytes */ .equ LGZONECAL, 10 conversion10:
push {r1-r4,lr} @ save registers
mov r3,r1
mov r2,#LGZONECAL
1: @ start loop
bl divisionpar10U @ unsigned r0 <- dividende. quotient ->r0 reste -> r1
add r1,#48 @ digit
strb r1,[r3,r2] @ store digit on area
cmp r0,#0 @ stop if quotient = 0
subne r2,#1 @ else previous position
bne 1b @ and loop
@ and move digit from left of area
mov r4,#0
2:
ldrb r1,[r3,r2]
strb r1,[r3,r4]
add r2,#1
add r4,#1
cmp r2,#LGZONECAL
ble 2b
@ and move spaces in end on area
mov r0,r4 @ result length
mov r1,#' ' @ space
3:
strb r1,[r3,r4] @ store space in area add r4,#1 @ next position cmp r4,#LGZONECAL ble 3b @ loop if r4 <= area size
100:
pop {r1-r4,lr} @ restaur registres
bx lr @return
/***************************************************/ /* division par 10 unsigned */ /***************************************************/ /* r0 dividende */ /* r0 quotient */ /* r1 remainder */ divisionpar10U:
push {r2,r3,r4, lr}
mov r4,r0 @ save value
ldr r3,iMagicNumber @ r3 <- magic_number raspberry 1 2
umull r1, r2, r3, r0 @ r1<- Lower32Bits(r1*r0) r2<- Upper32Bits(r1*r0)
mov r0, r2, LSR #3 @ r2 <- r2 >> shift 3
add r2,r0,r0, lsl #2 @ r2 <- r0 * 5
sub r1,r4,r2, lsl #1 @ r1 <- r4 - (r2 * 2) = r4 - (r0 * 10)
pop {r2,r3,r4,lr}
bx lr @ leave function
iMagicNumber: .int 0xCCCCCCCD /***************************************************/ /* integer division unsigned */ /***************************************************/ division:
/* r0 contains dividend */
/* r1 contains divisor */
/* r2 returns quotient */
/* r3 returns remainder */
push {r4, lr}
mov r2, #0 @ init quotient
mov r3, #0 @ init remainder
mov r4, #32 @ init counter bits
b 2f
1: @ loop
movs r0, r0, LSL #1 @ r0 <- r0 << 1 updating cpsr (sets C if 31st bit of r0 was 1) adc r3, r3, r3 @ r3 <- r3 + r3 + C. This is equivalent to r3 ? (r3 << 1) + C cmp r3, r1 @ compute r3 - r1 and update cpsr subhs r3, r3, r1 @ if r3 >= r1 (C=1) then r3 <- r3 - r1 adc r2, r2, r2 @ r2 <- r2 + r2 + C. This is equivalent to r2 <- (r2 << 1) + C
2:
subs r4, r4, #1 @ r4 <- r4 - 1
bpl 1b @ if r4 >= 0 (N=0) then loop
pop {r4, lr}
bx lr
</lang>
AutoHotkey
From AHK Forum <lang AutoHotkey>Gui, Add, Picture, x100 y100 w2 h2 +0x4E +HWNDhPicture CreatePixel("FF0000", hPicture) Gui, Show, w320 h240, Example return
CreatePixel(Color, Handle) { VarSetCapacity(BMBITS, 4, 0), Numput("0x" . Color, &BMBITS, 0, "UInt") hBM := DllCall("Gdi32.dll\CreateBitmap", "Int", 1, "Int", 1, "UInt", 1, "UInt", 24, "Ptr", 0, "Ptr") hBM := DllCall("User32.dll\CopyImage", "Ptr", hBM, "UInt", 0, "Int", 0, "Int", 0, "UInt", 0x2008, "Ptr") DllCall("Gdi32.dll\SetBitmapBits", "Ptr", hBM, "UInt", 3, "Ptr", &BMBITS) DllCall("User32.dll\SendMessage", "Ptr", Handle, "UInt", 0x172, "Ptr", 0, "Ptr", hBM) }</lang>
BASIC256
It seems that the program should be this. And the BASIC256 tutorial programs work on my ubuntu system. This program neither draws the pixel nor resizes the window. Can't see anything when I plot many spots. Oh well. I've tried the rgb(255,0,0) function as well as the fastgraphics/refresh statements. <lang BASIC256> rem http://rosettacode.org/wiki/Draw_a_pixel
graphsize 320, 240 color red plot 100, 100 </lang>
BBC BASIC
<lang bbcbasic> VDU 23, 22, 320; 240; 8, 8, 8, 0, 18, 0, 1, 25, 69, 100; 100;</lang>
C
Requires the WinBGIm library. <lang C>
- include<graphics.h>
int main() { initwindow(320,240,"Red Pixel");
putpixel(100,100,RED);
getch();
return 0; } </lang>
Commodore BASIC
Example 1: Commodore 64
There are no graphics commands in Commodore 64 BASIC. High resolution (hires) graphics are programmed by directly manipulating the hardware registers and memory.
The Commodore 64 hires bitmap is 320×200, subdivided into 8×8 cells starting at the top left and moving right. Each cell is addressed top to bottom by 8 bytes. Each byte controls a horizontal row of 8 bits. This requires calculation on the programmer's part to translate X,Y coordinates into a specific memory address/value combination (lines 30 through 60).
<lang gwbasic>10 REM PLOT A RED PIXEL AT 100,100 20 REM INITIALIZE BITMAP MODE 21 POKE 53280,0:PRINT CHR$(147);"CLEARING BITMAP... PLEASE WAIT..." 22 BASE=8192:FOR I=BASE TO BASE+7999:POKE I,0:NEXT 23 PRINT CHR$(147); 24 POKE 53272,PEEK(53272) OR 8:REM SET BITMAP MEMORY AT 8192 ($2000) 25 POKE 53265,PEEK(53265) OR 32:REM ENTER BITMAP MODE 26 REM PLOT PIXEL 30 X=100:Y=100 40 MEM=BASE+INT(Y/8)*320+INT(X/8)*8+(Y AND 7) 50 PX=7-(X AND 7) 60 POKE MEM,PEEK(MEM) OR 2^PX 65 REM WAIT FOR KEYPRESS 70 GET K$:IF K$="" THEN 70 75 REM CLEAR PIXEL, RETURN TO TEXT MODE 80 POKE MEM,0:POKE 53265,PEEK(53265) AND 223:POKE 53272,PEEK(53272) AND 247 90 POKE 53280,14:POKE 53281,6:POKE 646,14:END</lang>
Example 2: Commodore Plus 4 and 128 <lang gwbasic>10 COLOR 0,1:COLOR 1,3: REM SET BORDER TO BLACK AND PIXEL COLOR TO RED 15 GRAPHIC 1,1 : REM ENTER BITMAP GRAPHICS MODE AND CLEAR SCREEN 20 DRAW 1,100,100 : REM PLOT PIXEL AT 100,100 30 GET K$:IF K$="" THEN 30 40 GRAPHIC 0,1 : REM RETURN TO TEXT MODE</lang>
Delphi
Console version using windows api, thanks for RRUZ ([1]) <lang Delphi> program Draw_a_pixel;
{$APPTYPE CONSOLE}
{$R *.res}
uses
Windows, Messages, SysUtils;
var
Msg: TMSG; LWndClass: TWndClass; hMainHandle: HWND;
procedure Paint(Handle: hWnd); forward;
procedure ReleaseResources; begin
PostQuitMessage(0);
end;
function WindowProc(hWnd, Msg: Longint; wParam: wParam; lParam: lParam): Longint; stdcall; begin
case Msg of
WM_PAINT:
Paint(hWnd);
WM_DESTROY:
ReleaseResources;
end;
Result := DefWindowProc(hWnd, Msg, wParam, lParam);
end;
procedure CreateWin(W, H: Integer);
begin
LWndClass.hInstance := hInstance; with LWndClass do begin lpszClassName := 'OneRedPixel'; Style := CS_PARENTDC or CS_BYTEALIGNCLIENT; hIcon := LoadIcon(hInstance, 'MAINICON'); lpfnWndProc := @WindowProc; hbrBackground := COLOR_BTNFACE + 1; hCursor := LoadCursor(0, IDC_ARROW); end;
RegisterClass(LWndClass); hMainHandle := CreateWindow(LWndClass.lpszClassName, 'Draw a red pixel on (100,100)', WS_CAPTION or WS_MINIMIZEBOX or WS_SYSMENU or WS_VISIBLE, ((GetSystemMetrics(SM_CXSCREEN) - W) div 2), ((GetSystemMetrics (SM_CYSCREEN) - H) div 2), W, H, 0, 0, hInstance, nil);
end;
procedure ShowModal; begin
while GetMessage(Msg, 0, 0, 0) do begin TranslateMessage(Msg); DispatchMessage(Msg); end;
end;
procedure Paint(Handle: hWnd); var
ps: PAINTSTRUCT; Dc: HDC;
begin
Dc := BeginPaint(Handle, ps);
// Fill bg with white FillRect(Dc, ps.rcPaint, CreateSolidBrush($FFFFFF));
// Do the magic SetPixel(Dc, 100, 100, $FF);
EndPaint(Handle, ps);
end;
begin
CreateWin(320, 240); ShowModal();
end.
</lang>
- Output:
F#
Uses Windows Forms <lang fsharp>open System.Windows.Forms open System.Drawing
let f = new Form() f.Size <- new Size(320,240) f.Paint.Add(fun e -> e.Graphics.FillRectangle(Brushes.Red, 100, 100 ,1,1)) Application.Run(f)</lang>
Factor
<lang factor>USING: accessors arrays images images.testing images.viewer kernel literals math sequences ; IN: rosetta-code.draw-pixel
- draw-pixel ( -- )
B{ 255 0 0 } 100 100 <rgb-image> 320 240 [ 2array >>dim ]
[ * ] 2bi [ { 0 0 0 } ] replicate B{ } concat-as >>bitmap
[ set-pixel-at ] keep image-window ;
MAIN: draw-pixel</lang>
Forth
<lang forth>\ Bindings to SDL2 functions s" SDL2" add-lib \c #include <SDL2/SDL.h> c-function sdl-init SDL_Init n -- n c-function sdl-quit SDL_Quit -- void c-function sdl-createwindow SDL_CreateWindow a n n n n n -- a c-function sdl-createrenderer SDL_CreateRenderer a n n -- a c-function sdl-setdrawcolor SDL_SetRenderDrawColor a n n n n -- n c-function sdl-drawpoint SDL_RenderDrawPoint a n n -- n c-function sdl-renderpresent SDL_RenderPresent a -- void c-function sdl-delay SDL_Delay n -- void
- pixel ( -- )
$20 sdl-init drop s\" Rosetta Task : Draw a pixel\x0" drop 0 0 320 240 $0 sdl-createwindow ( window ) -1 $2 sdl-createrenderer
dup ( renderer ) 255 0 0 255 sdl-setdrawcolor drop
dup ( renderer ) 100 100 sdl-drawpoint drop
( renderer ) sdl-renderpresent
5000 sdl-delay sdl-quit
pixel</lang>
FreeBASIC
<lang freebasic>' version 27-06-2018 ' compile with: fbc -s console ' or: fbc -s gui
Screen 13 ' Screen 18: 320x200, 8bit colordepth 'ScreenRes 320, 200, 24 ' Screenres: 320x200, 24bit colordepth
If ScreenPtr = 0 Then
Print "Error setting video mode!" End
End If
Dim As UInteger depth, x = 100, y = 100
' what is color depth ScreenInfo ,,depth
If depth = 8 Then
PSet(x, y), 40 ' palette, index 40 = RGB(255, 0, 0)
Else
PSet(x, y), RGB(255, 0, 0) ' red
End If
' empty keyboard buffer While Inkey <> "" : Wend WindowTitle IIf(depth = 8, "Palette","True Color") + ", hit any key to end program" Sleep End</lang>
GB BASIC
The resolution of the Game Boy's screen is only 160×144, so the window requirement is out, but the pixel is easy. Also, GB BASIC doesn't support displaying the color red, so the Game Boy's grayscale equivalent, dark gray, is used instead: <lang GB BASIC>10 color 1 20 point 100,100</lang>
GML
<lang GML>draw_point(100, 100);</lang>
Go
<lang go>package main
import (
"fmt" "image" "image/color" "image/draw"
)
func main() {
rect := image.Rect(0, 0, 320, 240) img := image.NewRGBA(rect)
// Use green background, say.
green := color.RGBA{0, 255, 0, 255}
draw.Draw(img, rect, &image.Uniform{green}, image.ZP, draw.Src)
// Set color of pixel at (100, 100) to red
red := color.RGBA{255, 0, 0, 255}
img.Set(100, 100, red)
// Check it worked.
cmap := map[color.Color]string{green: "green", red: "red"}
c1 := img.At(0, 0)
c2 := img.At(100, 100)
fmt.Println("The color of the pixel at ( 0, 0) is", cmap[c1], "\b.")
fmt.Println("The color of the pixel at (100, 100) is", cmap[c2], "\b.")
}</lang>
- Output:
The color of the pixel at ( 0, 0) is green. The color of the pixel at (100, 100) is red.
Create a PNG image?
- <lang go>package main
import ( "image" "image/color" "image/draw" "image/png" "os" )
func main() { // Create a 320 x 240 image img := image.NewRGBA(image.Rect(0, 0, 320, 240)) // fill img in white draw.Draw(img, img.Bounds(), &image.Uniform{color.RGBA{0, 0, 0, 0}}, image.ZP, draw.Src) // Draw a red dot at (100, 100) img.Set(100, 100, color.RGBA{255, 0, 0, 255}) // Save to new.png w, _ := os.OpenFile("new.png", os.O_WRONLY|os.O_CREATE, 0600) defer w.Close() png.Encode(w, img) } </lang> GUI "window" rather than an image?
- <lang go>package main
// first run" go get github.com/zserge/webview" // simple GUI "window" import "github.com/zserge/webview"
func main() { // Open wikipedia in a 320*240 resizable window webview.Open("Minimal webview example", "https://en.m.wikipedia.org/wiki/Main_Page", 320, 240, true) }</lang>
Icon and Unicon
<lang unicon>#
- draw-pixel.icn
procedure main()
&window := open("pixel", "g", "size=320,240")
Fg("#ff0000")
DrawPoint(100, 100)
Event()
end</lang>
IS-BASIC
<lang IS-BASIC>100 SET VIDEO X 40:SET VIDEO Y 26:SET VIDEO MODE 5:SET VIDEO COLOR 0 110 OPEN #101:"video:" 120 DISPLAY #101:AT 1 FROM 1 TO 26 130 SET PALETTE BLACK,RED 140 PLOT 100,100</lang>
J
<lang J>require 'gl2' coinsert 'jgl2' wd'pc Rosetta closeok;cc task isidraw; set task wh 320 200;pshow' glpaint glpixel 100 100 [ glpen 1 1 [ glrgb 255 0 0 [ glclear </lang>
Java
Basic Implementation via subclass of JFrame: <lang Java>import java.awt.Color; import java.awt.Graphics; import javax.swing.JFrame;
public class DrawAPixel extends JFrame{ public DrawAPixel() { super("Red Pixel"); setSize(320, 240); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setVisible(true); } @Override public void paint(Graphics g) { g.setColor(new Color(255, 0, 0)); g.drawRect(100, 100, 1, 1); } public static void main(String[] args) { new DrawAPixel(); } } </lang> Advanced Implementation via subclass of JPanel (more powerful especially while repainting): <lang Java>import java.awt.Color; import java.awt.Graphics; import java.awt.image.BufferedImage; import javax.swing.JFrame; import javax.swing.JPanel;
public class DrawAPixel extends JPanel{ private BufferedImage puffer; private JFrame window; private Graphics g; public DrawAPixel() { window = new JFrame("Red Pixel"); window.setSize(320, 240); window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); window.setLayout(null); setBounds(0, 0, 320, 240); window.add(this); window.setVisible(true); } @Override public void paint(Graphics gr) { if(g == null) { puffer = (BufferedImage) createImage(getWidth(), getHeight()); g = puffer.getGraphics(); } g.setColor(new Color(255, 0, 0)); g.drawRect(100, 100, 1, 1); gr.drawImage(puffer, 0, 0, this); } public static void main(String[] args) { new DrawAPixel(); } } </lang>
Julia
<lang julia>using Gtk, Graphics
const can = @GtkCanvas() const win = GtkWindow(can, "Draw a Pixel", 320, 240)
draw(can) do widget
ctx = getgc(can) set_source_rgb(ctx, 255, 0, 0) move_to(ctx, 100, 100) line_to(ctx, 101,100) stroke(ctx)
end
show(can) const cond = Condition() endit(w) = notify(cond) signal_connect(endit, win, :destroy) wait(cond) </lang>
Kotlin
This task seems very similar to the Bitmap task and so therefore is the code to accomplish it. <lang scala>// Version 1.2.41
import java.awt.Color import java.awt.Graphics import java.awt.image.BufferedImage
class BasicBitmapStorage(width: Int, height: Int) {
val image = BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR)
fun fill(c: Color) {
val g = image.graphics
g.color = c
g.fillRect(0, 0, image.width, image.height)
}
fun setPixel(x: Int, y: Int, c: Color) = image.setRGB(x, y, c.getRGB())
fun getPixel(x: Int, y: Int) = Color(image.getRGB(x, y))
}
fun main(args: Array<String>) {
val bbs = BasicBitmapStorage(320, 240)
with (bbs) {
fill(Color.white) // say
setPixel(100, 100, Color.red)
// check it worked
val c = getPixel(100, 100)
print("The color of the pixel at (100, 100) is ")
println(if (c == Color.red) "red" else "white")
}
}</lang>
- Output:
The color of the pixel at (100, 100) is red
Lambdatalk
<lang scheme> 1) html/css
{div {@ style="position:relative;
left:0; top:0; width:320px; height:240px;
border:1px solid #000;"}
{div {@ style="position:absolute; left:100px; top:100px;
width:1px; height:1px; background:#f00; border:0;"}}}
2) svg
{svg {@ width="320" height="240"
style="border:1px solid #000;"}
{rect {@ x="100" y="100" width="1" height="1"
style="fill:#f00; stroke-width:0; stroke:#f00;"}}}
3) canvas
{canvas {@ id="canvas" width="320" height="240"
style="border:1px solid #000;"}}
{script
var canvas_pixel = function(x, y, canvas) {
var ctx = document.getElementById( canvas )
.getContext( "2d" );
ctx.fillStyle = "#f00";
ctx.fillRect(x,y,1,1);
};
setTimeout( canvas_pixel, 1, 100, 100, "canvas" )
}
</lang>
Lua
The luasdl2 library is required.
<lang lua>local SDL = require "SDL"
local ret = SDL.init { SDL.flags.Video } local window = SDL.createWindow { title = "Pixel", height = 320, width = 240 }
local renderer = SDL.createRenderer(window, 0, 0)
renderer:clear() renderer:setDrawColor(0xFF0000) renderer:drawPoint({x = 100,y = 100}) renderer:present()
SDL.delay(5000) </lang>
Mathematica/Wolfram Language
<lang Mathematica>CreateWindow[PaletteNotebook[{Graphics[{Red, Point[{100, 100}]}]}], WindowSize -> {320, 240}]</lang>
M2000 Interpreter
Version 2
M2000 Console used for text and graphics too. So for this version we plot a pixel in console and in a form (a window above console). Form is open as modal, but console is something different, so we can show or hide it.
All forms are above console (for any kind, modal or not modal form), and we can hide console using Title statement. So in this example we hide/show console (behind form window) by clicking the form. In any state of showing console, when we close form and Interpreter need to input from console (like in prompt state), console state get visible.
There is also a PSet statement for pixel drawing (from 9.5 version). Just replace the module call to PlotPixel with Pset.
<lang M2000 Interpreter>
Module CheckIt {
Module PlotPixel (a as single, b as single) {
Move a*TwipsX, b*TwipsX
Draw TwipsX, TwipsY
}
Cls 5,0 \\ clear console with Magenta (5) and set split screen from 0 (no split screen)
Pen #55FF77 {
PlotPixel 1000, 200
}
Wait 1000
Title "", 1
Declare DrawPixelForm Form
With DrawPixelForm, "Title", "Draw a Pixel at 100,100"
Layer DrawPixelForm {
\\ 12 for 12pt fonts
\\ use ; to center window
Window 12, 320*twipsx, 240*twipsy;
Cls #333333
Pen Color(255,0,0) {
PlotPixel 100, 100
}
}
\\ code to show/hide console clicking form
\\ console shown behind form
k=0
Function DrawPixelForm.Click {
Title "Rosetta Code Example", abs(k)
if k then show
k~
}
Method DrawPixelForm, "Show", 1
Declare DrawPixelForm Nothing
} CheckIt </lang> OutPut
Nim
<lang nim>import rapid/gfx
var
window = initRWindow()
.size(320, 240)
.title("Rosetta Code - draw a pixel")
.open()
surface = window.openGfx()
surface.loop:
draw ctx, step: ctx.clear(gray(0)) ctx.begin() ctx.point((100.0, 100.0, rgb(255, 0, 0))) ctx.draw(prPoints) discard step # Prevent unused variable warnings update step: discard step</lang>
Another version using SDL2. <lang Nim>import sdl2
discard sdl2.init(INIT_EVERYTHING)
let window = createWindow("Pixel", 100, 100, 320, 240, SDL_WINDOW_SHOWN) let renderer = createRenderer(window, -1, Renderer_Accelerated)
renderer.clear() renderer.setDrawColor((255u8, 0u8, 0u8, 0u8)) renderer.drawPoint(100, 100) renderer.present()
delay(5000)</lang>
Oberon
With basic module XYplane, the size of the drawing plane cannot be set. Tested with OBNC.
<lang Oberon>MODULE pixel;
IMPORT XYplane;
BEGIN XYplane.Open; XYplane.Dot(100, 100, XYplane.draw); REPEAT UNTIL XYplane.Key() = "q" END pixel. </lang>
Objeck
<lang objeck>use Game.SDL2; use Game.Framework;
class DrawPixel {
@framework : GameFramework;
function : Main(args : String[]) ~ Nil {
DrawPixel->New()->Run();
}
New() {
@framework := GameFramework->New(320, 240, "RGB");
@framework->SetClearColor(Color->New(0, 0, 0));
}
method : Run() ~ Nil {
if(@framework->IsOk()) {
e := @framework->GetEvent();
quit := false;
while(<>quit) {
@framework->FrameStart();
@framework->Clear();
while(e->Poll() <> 0) {
if(e->GetType() = EventType->SDL_QUIT) {
quit := true;
};
};
@framework->GetRenderer()->SetDrawColor(255, 0, 0, 255);
@framework->GetRenderer()->DrawPoint(100, 100);
@framework->Show();
@framework->FrameEnd();
};
}
else {
"--- Error Initializing Game Environment ---"->ErrorLine();
return;
};
leaving {
@framework->Quit();
};
}
} </lang>
OCaml
Using the Graphics library provided with the standard OCaml distribution:
<lang ocaml>module G = Graphics
let () =
G.open_graph ""; G.resize_window 320 240; G.set_color G.red; G.plot 100 100; ignore (G.read_key ())</lang>
run with:
$ ocaml graphics.cma draw_a_pixel.ml
<lang ocaml>open Sdl
let () =
let width, height = (320, 240) in Sdl.init [`VIDEO]; let window, renderer = Render.create_window_and_renderer ~width ~height ~flags:[] in let rgb = (255, 0, 0) and a = 255 in Render.set_draw_color renderer ~rgb ~a; Render.draw_point renderer (100, 100); Render.render_present renderer; Timer.delay 3000; Sdl.quit ()</lang>
run with:
$ ocaml -I $(ocamlfind query sdl2) sdl2.cma draw_a_pixel.ml
Ol
<lang scheme> (import (lib gl)) (import (OpenGL version-1-0))
- init
(glClearColor 0.3 0.3 0.3 1) (glOrtho 0 320 0 240 0 1)
- draw loop
(gl:set-renderer (lambda (mouse)
(glClear GL_COLOR_BUFFER_BIT) (glBegin GL_POINTS) (glColor3f 255 0 0) (glVertex2f 100 100) (glEnd)))
</lang>
Perl
<lang perl>use Gtk3 '-init';
my $window = Gtk3::Window->new(); $window->set_default_size(320, 240); $window->set_border_width(10); $window->set_title("Draw a Pixel"); $window->set_app_paintable(TRUE);
my $da = Gtk3::DrawingArea->new(); $da->signal_connect('draw' => \&draw_in_drawingarea); $window->add($da); $window->show_all();
Gtk3->main;
sub draw_in_drawingarea {
my ($widget, $cr, $data) = @_; $cr->set_source_rgb(1, 0, 0); $cr->set_line_width(1); $cr->rectangle( 100, 100, 1, 1); $cr->stroke;
}</lang>
Phix
with javascript_semantics include pGUI.e cdCanvas cdcanvas function redraw_cb(Ihandle /*ih*/, integer /*posx*/, integer /*posy*/) cdCanvasActivate(cdcanvas) cdCanvasPixel(cdcanvas, 100, 100, CD_RED) cdCanvasFlush(cdcanvas) return IUP_DEFAULT end function function map_cb(Ihandle ih) cdcanvas = cdCreateCanvas(CD_IUP, ih) return IUP_DEFAULT end function procedure main() IupOpen() Ihandle canvas = IupCanvas(NULL) IupSetAttribute(canvas, "RASTERSIZE", "320x240") IupSetCallback(canvas, "MAP_CB", Icallback("map_cb")) Ihandle dlg = IupDialog(canvas) IupSetAttribute(dlg, "TITLE", "Draw a pixel") IupSetCallback(canvas, "ACTION", Icallback("redraw_cb")) IupShow(dlg) if platform()!=JS then IupMainLoop() IupClose() end if end procedure main()
Processing
A static-mode sketch containing setting one pixel on the canvas pixels array:
<lang Processing>size(320, 240); set(100, 100, color(255,0,0));</lang>
The same sketch in active mode sketch is:
<lang Processing>void setup() {
size(320, 240); set(100, 100, color(255,0,0));
}</lang>
Or a pixel can be manipulated through loading and modifying the pixels array. The formula to access a pixel is x + y * image width.
<lang Processing>void setup() {
size(320, 240); loadPixels(); pixels[width*100 + 100] = color(255,0,0); updatePixels();
}</lang>
Processing can also draw a dot on the canvas using the `point()` command will also draw a dot on the canvas...
<lang Processing>size(320, 240); stroke(color(255,0,0)); point(100, 100);</lang>
...however, whether a point corresponds to a single pixel on the screen may depend on device-specific factors such as `pixelDensity()`, render features such as 2D / 3D mode or `smooth()`, or style settings such as `strokeWidth()` or `strokeCap()`.
PureBasic
<lang PureBasic>
If OpenWindow(0, 0, 0, 320, 240, "Rosetta Code Draw A Pixel in PureBasic")
If CreateImage(0, 320, 240) And StartDrawing(ImageOutput(0))
Plot(100, 100,RGB(255,0,0))
StopDrawing()
ImageGadget(0, 0, 0, 320, 240, ImageID(0))
EndIf
Repeat
Event = WaitWindowEvent()
Until Event = #PB_Event_CloseWindow
EndIf
</lang>
Python
<lang Python>from PIL import Image
img = Image.new('RGB', (320, 240)) pixels = img.load() pixels[100,100] = (255,0,0) img.show() </lang>
QB64
<lang qb64>Screen _NewImage(320, 240, 32) PSet (100, 100), _RGB(255, 0, 0)</lang>
QBasic
<lang qbasic>' http://rosettacode.org/wiki/Draw_a_pixel ' This program can run in QBASIC, QuickBASIC, gw-BASIC (adding line numbers) and VB-DOS SCREEN 1 COLOR , 0 PSET (100, 100), 2 END</lang>
Racket
<lang racket>#lang racket (require racket/draw) (let ((b (make-object bitmap% 320 240)))
(send b set-argb-pixels 100 100 1 1 (bytes 255 0 0 255)) b)</lang>
Raku
(formerly Perl 6)
Really? Draw a single pixel? Sigh.
<lang perl6>use GTK::Simple; use GTK::Simple::DrawingArea; use Cairo;
my $app = GTK::Simple::App.new(:title('Draw a Pixel')); my $da = GTK::Simple::DrawingArea.new; gtk_simple_use_cairo;
$app.set-content( $da ); $app.border-width = 5; $da.size-request(320,240);
sub rect-do( $d, $ctx ) {
given $ctx {
.rgb(1, 0, 0);
.rectangle(100, 100, 1, 1);
.fill;
}
}
my $ctx = $da.add-draw-handler( &rect-do ); $app.run;</lang>
ReScript
<lang rescript>type document // abstract type for a document object type context = { mutable fillStyle: string, }
@bs.val external doc: document = "document"
@bs.send external getElementById: (document, string) => Dom.element = "getElementById" @bs.send external getContext: (Dom.element, string) => context = "getContext"
@bs.send external fillRect: (context, int, int, int, int) => unit = "fillRect"
let canvas = getElementById(doc, "my_canvas") let ctx = getContext(canvas, "2d")
ctx.fillStyle = "#F00" fillRect(ctx, 100, 100, 1, 1)</lang>
<lang html><!DOCTYPE html>
<html>
<head>
<title>Draw a Pixel</title>
<style rel="stylesheet" type="text/css">
body {
background-color:#777;
} canvas {
background-color:#888; margin:60px 120px; border:1px solid #555; box-shadow: -1px 2px 6px 1px rgba(0,0,0,0.3);
} </style> </head> <body>
<canvas id="my_canvas" width="320" height="240">
No support for HTML5 Canvas.
</canvas>
<script type="text/javascript" src="_draw.js"></script>
<noscript>
No support for Javascript.
</noscript>
</body> </html></lang>
REXX
This REXX version only works for:
- PC/REXX
- Personal/REXX
<lang rexx>/*REXX program displays (draws) a pixel at a specified screen location in the color red.*/ parse upper version !ver . !pcrexx= 'REXX/PERSONAL'==!ver | 'REXX/PC'==!ver /*obtain the REXX interpreter version. */ parse arg x y txt CC . /*obtain optional arguments from the CL*/ if x== | x=="," then x= 100 /*Not specified? Then use the default.*/ if y== | y=="," then y= 100 /* " " " " " " */ if CC== | CC="," then CC= 4 /* " " " " " " */ if txt== | txt="," then tzt= '·' /* " " " " " " */
if ¬!pcrexx then do; say; say "***error*** PC/REXX[interpreter] isn't being used."; say
exit 23
end
call scrWrite x,y,txt,,,CC /*stick a fork in it, we're all done. */</lang>
Ring
<lang ring># Project : Draw a pixel
load "guilib.ring"
new qapp {
win1 = new qwidget() {
setwindowtitle("Drawing Pixels")
setgeometry(100,100,320,240)
label1 = new qlabel(win1) {
setgeometry(10,10,300,200)
settext("")
}
new qpushbutton(win1) {
setgeometry(200,200,100,30)
settext("draw")
setclickevent("draw()")
}
show()
}
exec()
}
func draw()
p1 = new qpicture()
color = new qcolor() {
setrgb(255,0,0,255)
}
pen = new qpen() {
setcolor(color)
setwidth(5)
}
new qpainter() {
begin(p1)
setpen(pen)
drawpoint(100,100)
endpaint()
}
label1 { setpicture(p1) show() }</lang>
Output image: Draw a pixel
Robotic
We can technically draw a pixel through the use of Sprites.
One of the requirements (fixed screen resolution) could not be met. <lang robotic> . "Set the sprite's reference character located at the" . "upper-left corner of the board (char 0)" set "SPR0_REFX" to 0 set "SPR0_REFY" to 0
. "Offset that reference by 256, leading to the first character" . "in the extended character set" set "SPR0_OFFSET" to 256
. "Set the width and height of the sprite" set "SPR0_WIDTH" to 1 set "SPR0_HEIGHT" to 1
. "Unbound the sprite, removing the grid restriction" set "SPR0_UNBOUND" to 1
. "Mark the sprite for display on the overlay (this may not be necessary)" set "SPR0_OVERLAY" to 1
set "xPos" to 100 set "yPos" to 100
. "Display the sprite at the given location" put c0c Sprite p00 at "('xPos')" "('yPos')" </lang>
I highly recommend you check out this tutorial for the usage of Sprites in order to get a better understanding of all this.
Ruby
<lang ruby>require 'gtk3'
Width, Height = 320, 240 PosX, PosY = 100, 100
window = Gtk::Window.new window.set_default_size(Width, Height) window.title = 'Draw a pixel'
window.signal_connect(:draw) do |widget, context|
context.set_antialias(Cairo::Antialias::NONE) # paint out bg with white # context.set_source_rgb(1.0, 1.0, 1.0) # context.paint(1.0) # draw a rectangle context.set_source_rgb(1.0, 0.0, 0.0) context.fill do context.rectangle(PosX, PosY, 1, 1) end
end
window.signal_connect(:destroy) { Gtk.main_quit }
window.show Gtk.main </lang>
Rust
- Output Image:
<lang rust>extern crate piston_window;
extern crate image;
use piston_window::*;
fn main() {
let (width, height) = (320, 240);
let mut window: PistonWindow =
WindowSettings::new("Red Pixel", [width, height])
.exit_on_esc(true).build().unwrap();
// Since we cant manipulate pixels directly, we need to manipulate the pixels on a canvas. // Only issue is that sub-pixels exist (which is probably why the red pixel looks like a smear on the output image) let mut canvas = image::ImageBuffer::new(width, height); canvas.put_pixel(100, 100, image::Rgba([0xff, 0, 0, 0xff]));
// Transform into a texture so piston can use it.
let texture: G2dTexture = Texture::from_image(
&mut window.factory,
&canvas,
&TextureSettings::new()
).unwrap();
// The window event loop.
while let Some(event) = window.next() {
window.draw_2d(&event, |context, graphics| {
clear([1.0; 4], graphics);
image(&texture,
context.transform,
graphics);
});
}
} </lang>
Scala
Scala idiom
A more Scalesque version could be with the use of its idiom:
- Output:
Best experienced in your browser with Scastie (remote JVM). <lang scala>import java.awt.image.BufferedImage import java.awt.Color import scala.language.reflectiveCalls
object RgbBitmap extends App {
class RgbBitmap(val dim: (Int, Int)) {
def width = dim._1
def height = dim._2
private val image = new BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR)
def apply(x: Int, y: Int) = new Color(image.getRGB(x, y))
def update(x: Int, y: Int, c: Color) = image.setRGB(x, y, c.getRGB)
def fill(c: Color) = {
val g = image.getGraphics
g.setColor(c)
g.fillRect(0, 0, width, height)
}
}
object RgbBitmap {
def apply(width: Int, height: Int) = new RgbBitmap(width, height)
}
/** Even Javanese style testing is still possible.
*/
private val img0 = new RgbBitmap(50, 60) { // Wrappers to enable adhoc Javanese style
def getPixel(x: Int, y: Int) = this(x, y)
def setPixel(x: Int, y: Int, c: Color) = this(x, y) = c
}
img0.fill(Color.CYAN)
img0.setPixel(5, 6, Color.BLUE)
// Testing in Java style
assert(img0.getPixel(0, 1) == Color.CYAN)
assert(img0.getPixel(5, 6) == Color.BLUE)
assert(img0.width == 50)
assert(img0.height == 60)
println("Tests successfully completed with no errors found.")
}</lang>
SmileBASIC
I almost said that the 320x240 requirement was not going to happen. Then I realised the 3DS bottom screen is exactly 320x240. <lang smilebasic>XSCREEN 3 DISPLAY 1 GPSET 100, 100, RGB(255, 0, 0) WAIT 60</lang>
Standard ML
Works with PolyML <lang Standard ML>open XWindows ; open Motif ;
val imgWindow = fn () =>
let
val shell = XtAppInitialise "" "demo" "top" [] [ XmNwidth 320, XmNheight 240 ] ;
val main = XmCreateMainWindow shell "main" [ XmNmappedWhenManaged true ] ;
val canvas = XmCreateDrawingArea main "drawarea" [ XmNwidth 320, XmNheight 240 ] ;
val usegc = DefaultGC (XtDisplay canvas) ;
val put = fn (w,s,t) => ( XSetForeground usegc 0xff0000 ;
XDrawPoint (XtWindow canvas) usegc ( XPoint {x=100,y=100} ) ; t);
in
( XtSetCallbacks canvas [ (XmNexposeCallback , put) ] XmNarmCallback ; XtManageChild canvas ; XtManageChild main ; XtRealizeWidget shell )
end;</lang> call
imgWindow () ;
Tcl
<lang tcl>package require Tcl 8.5 package require Tk
pack [canvas .c -width 320 -height 240 -bg #fff] -anchor nw .c create rectangle 100 100 100 100 -fill #f00 -outline ""</lang>
True BASIC
<lang truebasic>SET WINDOW 0, 320, 0, 240 SET COLOR 4 PLOT 100,100 END</lang>
VBA
Word <lang vb>Sub draw()
Dim sh As Shape, sl As Shape Set sh = ActiveDocument.Shapes.AddCanvas(100, 100, 320, 240) Set sl = sh.CanvasItems.AddLine(100, 100, 101, 100) sl.Line.ForeColor.RGB = RGB(Red:=255, Green:=0, Blue:=0)
End Sub</lang>
Wee Basic
Since the resolution of the Nintendo DS's bottom screen is only 256×192 (the same applies to the top screen), the window requirement is out, but the pixel is easy: <lang Wee Basic>keyhide plot 0 100,100,5 end</lang>
Wren
<lang ecmascript>import "dome" for Window import "graphics" for Canvas, Color
class Game {
static init() {
Window.title = "Draw a pixel"
Window.resize(320, 240)
Canvas.resize(320, 240)
var red = Color.rgb(255, 0, 0)
Canvas.pset(100, 100, red)
// check it worked
var col = Canvas.pget(100, 100)
System.print("The color of the pixel at (100, 100) is %(getRGB(col))")
}
static update() {}
static draw(dt) {}
static getRGB(col) { "{%(col.r), %(col.g), %(col.b)}" }
}</lang>
- Output:
$ ./dome draw_pixel.wren
The color of the pixel at (100, 100) is {255, 0, 0}
X86 Assembly
This doesn't quite meet the requirements, but it shows how little code is needed to draw a pixel on an IBM-PC VGA screen. The executable program is a mere 32 bytes long. The "window" in this case is 320x200. Palette register 28 hex is set to bright red by the BIOS at boot-up time. About half the code is used to wait for a keystroke before returning to the OS, so the pixel can be seen. Borland's tasm and tlink /t were used to create an executable .com file. <lang X86>
.model tiny
.code
org 100h
start: mov ax, 0013h ;set 320x200x8 graphic screen
int 10h
push 0A000h ;point to graphic memory segment
pop es
mov byte ptr es:[320*100+100], 28h ;draw bright red pixel
mov ah, 0 ;wait for keystroke
int 16h
mov ax, 0003h ;restore normal text mode screen
int 10h
ret ;return to OS
end start
</lang>
XPL0
This is all that's required to plot a pixel on the Raspberry Pi version of XPL0. It can do tens of millions of them per second. (FB = Frame Buffer.) <lang XPL0>[SetFB(320, 240, 24); Point(100, 100, $FF0000)]</lang>
Yabasic
<lang Yabasic>open window 320, 240 color 255, 0, 0 dot 100, 100</lang>
ZX Spectrum Basic
The ZX Spectrum screen is only 256x224 (unless you're running one of the games like Starion or Dark Star which used scary machine code timing tricks to draw on the border), meaning the window requirement is out, but the pixel is easy: <lang zxbasic>PLOT INK 2;100,100</lang>
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