- How to retrieve the components of the color?
- Using the drawing functions
- dPixelColor, Zoom and automatic scrollbars
- Drawing in PHP
- Drawing in Browser code
In french: dPixelCouleur
// Identify the color of the pixel (15, 25)
// in the Image control named "IMG_Drawing"
ResColor = dPixelColor(IMG_ImageDrawing, 15, 25)
<Result> = dPixelColor([<Image>, ] <X-coordinate> , <Y-coordinate>)
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
Horizontal position of pixel to use.
Vertical position of pixel to use.
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
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).
Drawing in 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.
Drawing in Browser code
Some drawing functions are available in Browser code. The drawing functions in Browser code are based on the HTML 5 standard. More specifically, these functions are based on the "canvas" tag of HTML 5.
The drawing features in browser code are available for the recent browsers only (supporting the HTML 5 standard). To find out whether the drawing features are proposed by your browser, use DrawingAvailable
Caution: To use the drawing functions with Internet Explorer 9, the project must include the reference to the DTD file. To do so, the HTML mode must be "HTML 4.01 Transitional + DTD". This option is available in the "Advanced" tab of the description window of project.
Reminder: To open the project description window, go to the "Project" tab, "Project" group and click "Description".
Special case: Drawing in the browser of an Android phone: The browser drawing functions are only available starting with version 3 of Android.
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