Task
Create a window and draw a pixel in it, subject to the following:
::# the window is 640 x 480 ::# the color of the pixel must be yellow (255,255,0) ::# the position of the pixel is random
C
Same as the [[Draw a pixel]] task, uses the random number functions of stdlib.h to plot a random point. Requires the [http://www.cs.colorado.edu/~main/bgi/cs1300/ WinBGIm] library.
#include<graphics.h>
#include<stdlib.h>
#include<time.h>
int main()
{
srand(time(NULL));
initwindow(640,480,"Yellow Random Pixel");
putpixel(rand()%640,rand()%480,YELLOW);
getch();
return 0;
}
Factor
USING: kernel random raylib.ffi ;
640 480 2dup "random yellow pixel" init-window [ random ] bi@
60 set-target-fps [ window-should-close ] [
begin-drawing BLACK clear-background 2dup YELLOW draw-pixel
end-drawing
] until close-window
FreeBASIC
' version 04-07-2018
' compile with: fbc -s console
' or: fbc -s gui
Screen 18, 24 ' Screen 18: 640x480, 24bit colordepth
'ScreenRes 640, 480, 24 ' Screenres: 640x480, 24bit colordepth
If ScreenPtr = 0 Then
Print "Error setting video mode!"
End
End If
Randomize Timer
Dim As UInteger x = Rnd * 640, y = Rnd * 480
PSet (x, y), RGB(255,255,0) ' yellow
' empty keyboard buffer
While Inkey <> "" : Wend
WindowTitle "0, 0 is top left, pixel is at " & x & ", " & y & " hit any key to end program"
Sleep
End
Go
package main
import (
"fmt"
"image"
"image/color"
"image/draw"
"math/rand"
"time"
)
func main() {
rect := image.Rect(0, 0, 640, 480)
img := image.NewRGBA(rect)
// Use blue background, say.
blue := color.RGBA{0, 0, 255, 255}
draw.Draw(img, rect, &image.Uniform{blue}, image.ZP, draw.Src)
// Set color of a random pixel to yellow
yellow := color.RGBA{255, 255, 0, 255}
width := img.Bounds().Dx()
height := img.Bounds().Dy()
rand.Seed(time.Now().UnixNano())
x := rand.Intn(width)
y := rand.Intn(height)
img.Set(x, y, yellow)
// Check there's exactly one random yellow pixel.
cmap := map[color.Color]string{blue: "blue", yellow: "yellow"}
for i := 0; i < width; i++ {
for j := 0; j < height; j++ {
c := img.At(i, j)
if cmap[c] == "yellow" {
fmt.Printf("The color of the pixel at (%d, %d) is yellow\n", i, j)
}
}
}
}
Sample output:
The color of the pixel at (525, 163) is yellow
javascript
let w = window.open("", "", "width=640,height=480");
let canvas = document.createElement("canvas");
canvas.width = 640;
canvas.height = 480;
w.document.body.appendChild(canvas);
w.document.body.style.margin = 0;
let ctx = canvas.getContext("2d");
ctx.fillStyle = "#FFFF00";
let x = Math.random() * 641;
let y = Math.random() * 481;
ctx.fillRect(x, y, 1, 1);
Julia
using Gtk, Graphics
const can = @GtkCanvas()
const win = GtkWindow(can, "Draw a Pixel 2", 640, 480)
draw(can) do widget
ctx = getgc(can)
set_source_rgb(ctx, 255, 255, 0)
x = rand(collect(1:639))
y = rand(collect(1:480))
println("The pixel is at $x, $y.")
move_to(ctx, x, y)
line_to(ctx, x + 1, y)
stroke(ctx)
end
draw(can)
show(can)
const cond = Condition()
endit(w) = notify(cond)
signal_connect(endit, win, :destroy)
wait(cond)
Kotlin
This is a variation of the [[Draw a pixel]] task and so therefore is the code to accomplish it.
// Version 1.2.41
import java.awt.Color
import java.awt.Graphics
import java.awt.image.BufferedImage
import java.util.Random
class BasicBitmapStorage(width: Int, height: Int) {
val image = BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR)
fun fill(c: Color) {
val g = image.graphics
g.color = c
g.fillRect(0, 0, image.width, image.height)
}
fun setPixel(x: Int, y: Int, c: Color) = image.setRGB(x, y, c.getRGB())
fun getPixel(x: Int, y: Int) = Color(image.getRGB(x, y))
}
fun main(args: Array<String>) {
val rand = Random()
val bbs = BasicBitmapStorage(640, 480)
with (bbs) {
fill(Color.white) // say
val x = rand.nextInt(image.width)
val y = rand.nextInt(image.height)
setPixel(x, y, Color.yellow)
// check there's exactly one random yellow pixel
for (i in 0 until image.width) {
for (j in 0 until image.height) {
if (getPixel(i, j) == Color.yellow) {
println("The color of the pixel at ($i, $j) is yellow")
}
}
}
}
}
Sample output:
The color of the pixel at (296, 15) is yellow
Perl
use Gtk3 '-init';
my $width = 640;
my $height = 480;
my $window = Gtk3::Window->new();
$window->set_default_size($width, $height);
$window->set_border_width(10);
$window->set_title("Draw Pixel 2");
$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, 1, 0);
$cr->set_line_width(1);
$cr->rectangle( int rand $width , int rand $height, 1, 1);
$cr->stroke;
}
Perl 6
Coordinates of random pixel displayed in window title. To make the single pixel show up better I filled in the drawing area background with black to get better contrast.
use GTK::Simple;
use GTK::Simple::DrawingArea;
use Cairo;
my ($w, $h) = 640, 480;
my ($x, $y) = (^$w).pick, (^$h).pick;
my $app = GTK::Simple::App.new(:title("Draw Pixel 2 @ $x,$y"));
my $da = GTK::Simple::DrawingArea.new;
gtk_simple_use_cairo;
$app.set-content( $da );
$app.border-width = 5;
$da.size-request($w, $h);
sub rect-do( $d, $ctx ) {
given $ctx {
.rgb(0, 0, 0);
.rectangle(0, 0, $w, $h);
.fill;
.rgb(1, 1, 0);
.rectangle($x, $y, 1, 1);
.fill;
}
}
my $ctx = $da.add-draw-handler( &rect-do );
$app.run;
Phix
Resize the window to see the pixel jumping about.
include pGUI.e
Ihandle dlg, canvas
cdCanvas cddbuffer, cdcanvas
function redraw_cb(Ihandle /*ih*/, integer /*posx*/, integer /*posy*/)
atom {w,h} = IupGetIntInt(canvas, "DRAWSIZE")
cdCanvasActivate(cddbuffer)
cdCanvasClear(cddbuffer)
cdCanvasPixel(cddbuffer, rand(w), rand(h), CD_YELLOW)
cdCanvasFlush(cddbuffer)
return IUP_DEFAULT
end function
function map_cb(Ihandle ih)
cdcanvas = cdCreateCanvas(CD_IUP, ih)
cddbuffer = cdCreateCanvas(CD_DBUFFER, cdcanvas)
cdCanvasSetBackground(cddbuffer, CD_BLACK)
return IUP_DEFAULT
end function
procedure main()
IupOpen()
canvas = IupCanvas(NULL)
IupSetAttribute(canvas, "RASTERSIZE", "240x50")
IupSetCallback(canvas, "MAP_CB", Icallback("map_cb"))
IupSetCallback(canvas, "ACTION", Icallback("redraw_cb"))
dlg = IupDialog(canvas)
IupSetAttribute(dlg, "TITLE", "Draw pixel")
IupCloseOnEscape(dlg)
IupShow(dlg)
IupSetAttribute(canvas, "RASTERSIZE", NULL)
IupMainLoop()
IupClose()
end procedure
main()
Racket
#lang racket/gui
(define WIDTH 640)
(define HEIGHT 480)
(define COLOR (make-color 255 255 0))
(define BACKGROUND-COLOR (make-color 0 0 0))
(define frame (new frame%
[label "Draw Pixel"]
[width WIDTH]
[height HEIGHT]))
(new canvas% [parent frame]
[paint-callback
(λ (canvas dc)
(send dc set-background BACKGROUND-COLOR)
(send dc clear)
(send dc set-pen COLOR 1 'solid)
(send dc draw-point (random WIDTH) (random HEIGHT)))])
(send frame show #t)
Ring
# Project : Draw pixel 2
load "guilib.ring"
new qapp {
nwidth = 320
nheight= 240
win1 = new qwidget() {
setwindowtitle("Draw Pixel 2")
setgeometry(100,100,640,480)
label1 = new qlabel(win1) {
setgeometry(10,10,640,480)
settext("")
}
new qpushbutton(win1) {
setgeometry(200,400,100,30)
settext("draw")
setclickevent("draw()")
}
new qpushbutton(win1) {
setgeometry(300,400,100,30)
settext("get pixel color")
setclickevent("PixelColor()")
}
show()
}
exec()
}
func draw()
p1 = new qpicture()
color = new qcolor() {
setrgb(255,255,0,255)
}
pen = new qpen() {
setcolor(color)
setwidth(10)
}
new qpainter() {
begin(p1)
setpen(pen)
x = random(nwidth-1) + 1
y = random(nheight-1) + 1
see "x = " + x + " y = " + y + nl
drawpoint(x,y)
endpaint()
}
label1 { setpicture(p1) show() }
func PixelColor()
oapp = new qapp(0,null) {
screen = win1.windowhandle().screen()
pixmap = screen.grabwindow(0,0,0,-1,-1)
image = pixmap.toimage()
color = image.pixel(100,100)
mycolor = new qcolor()
mycolor.setrgb(255,255,0,255)
see nl+"red : " + mycolor.red() + nl
see "green : " + mycolor.green() + nl
see "blue : " + mycolor.blue() + nl
}
Outputimage:
[https://www.dropbox.com/s/n31ppq8cu9ipru8/CalmoSoftPixelColor.jpg?dl=0 Draw pixel 2]
Scala
Java Swing Interoperability
{{Out}}See it yourself by running in your browser either by [https://scastie.scala-lang.org/9jfWoH2uRomUBKDBzFGzkw Scastie (remote JVM)].
import java.awt.image.BufferedImage
import java.awt.Color
import scala.language.reflectiveCalls
object RgbBitmap extends App {
// 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
}
class RgbBitMap(val dim: (Int, Int)) {
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)
}
def width = dim._1
def height = dim._2
}
private val (x,y) = (util.Random.nextInt(50), util.Random.nextInt(60))
img0.fill(Color.CYAN)
img0.setPixel(x, y, Color.BLUE)
// Testing in Java style
assert(img0.getPixel(x, y) == Color.BLUE)
assert(img0.width == 50)
assert(img0.height == 60)
println("Tests successfully completed with no errors found.")
}