dPixelColor (Function)

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How to retrieve the components of the color?

Using the drawing functions

dPixelColor, Zoom and automatic scrollbars

Pattern and PHP

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dPixelColor (Function)

In french: dPixelCouleur

Identifies the color of a pixel found:

in an Image control,
in an Image variable.
This type of variable is not available.

Versions 16 and later

This function is now available for Android applications.

New in version 16

This function is now available for Android applications.

Versions 17 and later

This function is now available for iPhone/iPad applications.

New in version 17

This function is now available for iPhone/iPad applications.

Example

See additional examples

// 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

Versions 24 and later
Image to use. This image can correspond to:
the name of an Image control.
the name of an Image variable.
This type of variable is not available.
If this parameter is not specified, the image specified in 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.
New in version 24
Image to use. This image can correspond to:
the name of an Image control.
the name of an Image variable.
This type of variable is not available.
If this parameter is not specified, the image specified in 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.
Image to use. This image can correspond to:
the name of an Image control.
the name of an Image variable.
This type of variable is not available.
If this parameter is not specified, the image specified in 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 top 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.
Versions 24 and later
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. The dStartDrawing function becomes unnecessary. This function must be deleted.
Versions 25 and later
This syntax is now available.
New in version 25
This syntax is now available.
This syntax is now available.
New in version 24
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. The dStartDrawing function becomes unnecessary. This function must be deleted.
Versions 25 and later
This syntax is now available.
New in version 25
This syntax is now available.
This syntax is now available.
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. The dStartDrawing function becomes unnecessary. This function must be deleted.
Versions 25 and later
This syntax is now available.
New in version 25
This syntax is now available.
This syntax is now available.

dPixelColor, Zoom and automatic scrollbars

The option "Automatic scrollbars and zoom" available on an Image control is incompatible with dPixelColor. If this option is used on the Image control, dPixelColor freezes the image in the control. The zoom and the scrollbars are also frozen.

Pattern and PHP

In PHP, the drawing functions are based on the graphic library GD. This library is commonly used by the PHP hosting companies and therefore it is always enabled. The version of the GD library must be version 2.0.28 (or later). This library can be downloaded from the PHP site.

To enable (if necessary) this library locally, the following elements are required:

PHP installed.
the PHP.INI file found in the Windows directory must contain the following line: "extension=php_gd2.dll" (instead of ";extension=php_gd2.dll").
the php_gd2.dll file must exist in the directory of PHP extensions. This directory is defined in the PHP.INI file by the "extension_dir" variable.

Component: wd260obj.dll