dSlice (Function)

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dSlice

Presentation

Example

Coordinates

Non-solid figure

Drawing with opacity or anti-aliasing

Using the drawing functions

Drawing in PHP

Drawing in Browser code

Related examples

See also

dSlice (Function)

In french: dPortion

Draws a circle section or an ellipse section:

in an Image control,
in a variable of type Image.
This type of variable is not available.
in a variable of type WDPic (on the background layer),
in a variable of type picLayer.

Caution: A specific configuration is required to use this function in Linux. For more details, see The drawings.

Example

// Initialize the drawing in an Image control
dStartDrawing(IMG_Drawing)

// Draw a circle section whose
// background is light yellow and whose border is light blue
dSlice(10, 10, 50, 50, 20, 20, 40, 50, LightYellow, LightBlue)

// Draw a circle section whose
// background is light yellow and whose border is light blue
dSlice(IMG_Drawing, 10, 10, 50, 50, 20, 20, 40, 50, LightYellow, LightBlue)

Syntax

dSlice([<Image>, ] <X1> , <Y1> , <X2> , <Y2> , <X3> , <Y3> , <X4> , <Y4> [, <Background color> [, <Line color>]])

<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.
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, it is necessary to define the drawing destination with dStartDrawing.

<X1>: Integer

X-coordinate of the upper-left corner of the rectangle containing the circle. These coordinates are expressed in pixels.

<Y1>: Integer

Y-coordinate of the upper-left corner of the rectangle containing the circle. These coordinates are expressed in pixels.

<X2>: Integer

X-coordinate of the lower-right corner of the rectangle containing the circle. These coordinates are expressed in pixels.

<Y2>: Integer

Y-coordinate of the lower-right corner of the rectangle containing the circle. These coordinates are expressed in pixels.

<X3>: Integer

X-coordinate of the start point of the circle section. These coordinates are expressed in pixels.

<Y3>: Integer

Y-coordinate of the start point of the circle section. These coordinates are expressed in pixels.

<X4>: Integer

X-coordinate of the end point of the circle section. These coordinates are expressed in pixels.

<Y4>: Integer

Y-coordinate of the end point of the circle section. These coordinates are expressed in pixels.

<Background color>: Integer or constant (optional)

Background color of the circle section. This color can correspond to:
an RGB color (returned by RGB),
an HSL color (returned by HSL),
a WLanguage preset color,
a variable of type Color.
If this parameter is not specified, the background color:
is Transparent if dBackground has not been used beforehand,
corresponds to the color specified in the last call to dBackground.

<Line color>: Integer or constant (optional)

Color of the line for the circle section. This color can correspond to:
an RGB color (returned by RGB),
an HSL color (returned by HSL),
a WLanguage preset color,
a variable of type Color.
If this parameter is not specified, the line color:
corresponds to the color specified in the last call to dPen,
is the same as the background color if dPen has not been used.

Remarks

Coordinates

If the start point and the end point are not located on the border of the circle (or on the border of the ellipse), the point taken into account corresponds to the intersection between the circle and the line that joins the specified point and the center of the rectangle (which means the center of the circle).

Coordinates are specified with respect to the upper-left corner of the image or Image control (coordinates: (0,0)).

The drawing sections are drawn anticlockwise.

Non-solid figure

To draw a non-solid figure (without taking into account the center of the circle), use dChord.

Drawing with opacity or anti-aliasing

For a drawing with opacity (dStartDrawing with the dWithOpacity constant) or anti-aliasing (dChangeMode with the drawAntiAliasing constant), the outline is drawn inside the section: therefore, the line is partly combined with the inside of the section. If the line is very thick, it will be displayed in two colors.

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.
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.

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.

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

Business / UI classification: Neutral code

Component: wd280pnt.dll