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  • Coordinates
  • How to retrieve the components of the color?
  • Using the drawing functions
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Stored procedures
Identifies the color of a pixel:
  • in an Image control,
  • in a variable of type Image.
// Identify the color of the pixel (15, 25)
// in the Image control named "IMG_Drawing"
ResColor = dPixelColor(IMG_ImageDrawing, 15, 25)
Syntax
<Result> = dPixelColor([<Image>, ] <X-coordinate> , <Y-coordinate>)
<Result>: Integer
Color of the specified pixel in RGB format.
Caution: the value returned may differ according to the display configuration (resolution, ...).
<Image>: Optional control name or optional Image, WDPic or picLayer variable
AndroidiPhone/iPadIOS WidgetMac Catalyst Image to use. The image can correspond to:
  • the name of an Image control.
  • the name of a variable of type Image.
If this parameter is not specified, the image handled by dStartDrawing will be used.
This parameter is not available in a report. To specify the image to use, dStartDrawing must be used before the call to dPixelColor.
<X-coordinate>: Integer
Horizontal position of pixel to use.
<Y-coordinate>: Integer
Vertical position of pixel to use.
Remarks

Coordinates

Coordinates are given in pixels with respect to the upper-left corner of the image (coordinates: (0.0)).
To retrieve the position of a mouse click in an Image control, use MouseXPos and MouseYPos.

How to retrieve the components of the color?

To retrieve the components of the color returned by dPixelColor:
  • To get the red component, use RGBRed (or perform a division modulo 256 of <Result>),
  • To get the green component, use RGBGreen (or perform a division modulo 256 of <Result>/256),
  • To get the blue component, use RGBBlue (or perform a division modulo 256 of <Result>/256/256).

Using the drawing functions

The drawing functions can be used according to 2 methods:
  • Method 1: Using dStartDrawing
    • dStartDrawing must be called before any other drawing function. dStartDrawing is used to define the element (Image control or variable) to which the drawing functions will be applied.
    • When drawing on an Image control:
      • The drawing functions operate on a copy ("bitmap") of the image. You can use the drawing functions of Windows (via API or CallDLL32) but these functions must use the DC (Device Context) returned by dStartDrawing.
      • dEndDrawing and dStartDrawing must not be called in the same process.
        The drawing will not be displayed if dEndDrawing and dStartDrawing are called in the same process: it will be automatically erased.
  • AndroidiPhone/iPadIOS WidgetMac Catalyst Method 2: indicating the drawing target directly in the syntax (via a parameter)
    The <Image> parameter is used to specify directly the target of the drawing. dStartDrawing becomes useless. This function must be deleted.
Component: wd290obj.dll
Minimum version required
  • Version 9
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Last update: 01/18/2024

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