Color of a screen pixel: Difference between revisions

==={{header|Applesoft BASIC}}===

[http://en.wikipedia.org/wiki/Apple_II_graphics#Low-Resolution_.28Lo-Res.29_graphics Low-Resolution (Lo-Res) graphics] 40x48 16 colors, page 1

<lang Applesoft BASIC>X = PDL (0) * 5 / 32

Y = PDL (1) * 3 / 16

COLOR= SCRN( X,Y)</lang>

==={{header|Liberty BASIC}}===

<lang lb>'This examples requires the Windows API

Struct point, x As long, y As long

hDC = GetDC(0)

result = GetCursorPos()

Print GetPixel(hDC, point.x.struct, point.y.struct)

Call ReleaseDC 0, hDC

End

Sub ReleaseDC hWnd, hDC

CallDLL #user32,"ReleaseDC", hWnd As uLong, hDC As uLong, ret As Long

End Sub

Function GetDC(hWnd)

CallDLL #user32, "GetDC", hWnd As uLong, GetDC As uLong

End Function

Function GetCursorPos()

CallDLL #user32, "GetCursorPos", point As struct, GetCursorPos As uLong

End Function

Function GetPixel(hDC, x, y)

CallDLL #gdi32, "GetPixel", hDC As uLong, x As long, y As long, GetPixel As long

End Function</lang>

==={{header|PureBasic}}===

Return the color used at the x,y position in the current output. If the current output has an alpha channel then the result will be a 32bit RGBA value, otherwise it will be a 24bit RGB value. The color can be split in their RGB and alpha values by using the Red(), Green(), Blue() and Alpha() functions.

<lang PureBasic>Color = Point(x, y)</lang>

To get the colour of a pixel on the screen when it is not managed by PureBasic (ie. from other programs' windows), it is necessary to use Windows API. This works only under Windows.

<lang PureBasic>

hDC = GetDC_(0)

Color = GetPixel_(hDC, x, y)

ReleaseDC_(0, hDC)</lang>

This work fine!!

<lang PureBasic>poz.point

If OpenWindow(0,0,0,100,45,"Get pixel color at cursor position",#PB_Window_MinimizeGadget)

TextGadget(0,0,0,50,12,"Red: ")

TextGadget(1,0,15,50,12,"Green: ")

TextGadget(2,0,30,50,12,"Blue: ")

TextGadget(3,50,0,50,12,"")

TextGadget(4,50,15,50,12,"")

TextGadget(5,50,30,50,12,"")

hDC = GetDC_(0)

Repeat

oldx=poz\x

oldy=poz\y

GetCursorPos_(@poz)

Color = GetPixel_(hDC, poz\x, poz\y)

If poz\x<>oldx Or poz\y<>oldy

SetGadgetText(3,Str(Red(color)))

SetGadgetText(4,Str(Green(color)))

SetGadgetText(5,Str(Blue(color)))

EndIf

event=WaitWindowEvent(200)

Until event=#PB_Event_CloseWindow

ReleaseDC_(0, hDC)

EndIf</lang>

==={{header|TI-89 BASIC}}===

Only the graph screen can be read.

<lang ti89b>pxlTest(y, x) © returns boolean</lang>