- Using the drawing functions
- Drawing in an image with opacity
- Drawing in PHP
- Drawing in Browser code
In french: dPixelOpacité
// Identify the opacity of the pixel (15, 25)
// on the "IMG_ImageDrawing" control
ResOpacity = dPixelOpacity(IMG_ImageDrawing, 15, 25)
<Result> = dPixelOpacity([<Image>, ] <X-coordinate> , <Y-coordinate>)
Opacity of specified pixel (included between 0 for transparent and 255 for opaque).
<Image>: Optional control name or optional Image, WDPic or picLayer variable
Image to use. The image can correspond to:
- the name of an Image control.
- the name of a variable of type Image.
This type of variable is not available.
- the name of a variable of type WDPic. Only the background layer will be handled.
- the name of a variable of type picLayer.
If this parameter is not specified, the image handled by dStartDrawing
will be used.
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
Drawing in an image with opacity
To specify that the drawing in the image supports opacity (Alpha channel), use dStartDrawing
and the dWithOpacity
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 project description window.
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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