<WDPic variable>.StartDrawing (Function)

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<WDPic variable>.StartDrawing (Function)

In french: <Variable WDPic>.DébutDessin

Indicates that the drawing functions that will be used are intended for a variable of type WDPic.

Remark: Function <WDPic variable>.StartDrawing initializes all parameters required to create (or continue) a drawing for a given element.

Example

MyWDPic is WDPic = "Test.gif"
// Start of drawing 
ResDrawing = MyWDPic.StartDrawing()
// Drawings in MyWDPic
...
// End of drawings in MyWDPic
IMG_MyDrawing = MyWDPic

MyWDPic is WDPic = "Test.gif"
MyWDPic.StartDrawing()
MyWDPic.Font("Arial", 12, iNormal, 0)
MyWDPic.DrawText(4, 0, "I'm writing in a WDPic variable!")
IMG_MyDrawing = MyWDPic

<Result> = <WDPic image>.StartDrawing([<Options>])

<Result>: Boolean

True if the drawing was initialized,
False otherwise.

<WDPic image>: WDPic variable

Name of the WDPic variable to be used. Only the background layer will be handled.

<Options>: Optional Integer constant (or combination of constants)

Drawing options:
dGridlinesOpacity The drawing is displayed over gridlines in order to highlight the transparent or semi-transparent sections of the drawing. The gridlines are not saved in the image.
dNoErase Does not erase the drawing in the variable.
dOnChart Used to draw in a variable in which a chart has already been drawn. In this case, the chart drawing is not erased.
dWithOpacity Allows managing opacity in the different drawing functions used with the variable. Used for example to create a PNG drawing with an Alpha channel.

No drawing option is used if this parameter is not specified.

Remarks

Use in prefix syntax

<WDPic variable>.StartDrawing must be called before the other drawing functions. <WDPic variable>.StartDrawing makes it possible to define the drawing options used on the WDPic variable.

Drawing with opacity

By creating a drawing that supports opacity, you can easily save PNG images with an Alpha channel.

To save a PNG drawing with an Alpha channel:

Use the <WDPic variable>.StartDrawing function. This function is used to define, if necessary, the element onto which the drawing functions will be applied as well as the drawing mode. The dWithOpacity constant is used to indicate that the drawing will manage the opacity. The dGridlinesOpacity constant is used to display gridlines underneath the different drawing areas.

Configure the opacity of your drawings with the following functions:


<WDPic variable>.Background	Declares the background color and its opacity for the next drawings.
<WDPic variable>.DrawPoint	Declares the color of the points and their opacity for the next drawings.
<WDPic variable>.Pen	Declares the color of the lines and their opacity for the next drawings.

Remark: The <WDPic variable>.PixelOpacity function is used to determine the opacity of a point.

Use <Image>.SavePNG to save your drawing in PNG format with alpha channel (opacity).

Limit In "Opacity management" mode, the <WDPic variable>.DrawText function is limited to the use of TrueType fonts.

Related Examples:

Unit examples (WINDEV): The drawing functions

[ + ] Using the main drawing functions of WINDEV to:
- Initialize an Image control for drawing
- Draw simple shapes
- Write a text into a drawing
- Change the color in a drawing

Component: wd300pnt.dll