dPolyline (Function)

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dPolyline (Function)

In french: dPolyligne

Draws a line composed of multiple segments:

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.

The first coordinate indicates the starting point of the first segment, then each coordinate indicates the end of the previous segment and the beginning of the next segment.

Example

dStartDrawing(IMG_Drawing)
// Draws a 4-pixel thick, green dotted line
dPen(DarkGreen, 2, 4)
// Line composed of 4 segments
dPolyline(4, 10, 100, 50, 60, 80, 90, 150, 13)

dStartDrawing(IMG_Drawing)
dPen(DarkGreen, 2, 4)
// Draw a line from an array of point coordinates (syntax 2)
arrCoordinatesXY is array of 0 by 2 int = [[2, 3], [14, 100], [10,70], [50, 80]]
dPolyline(arrCoordinatesXY)

dPen(IMG_Drawing, DarkGreen, 2, 4)
arrCoordinatesXY2 is array of 0 int = [2, 2, 140, 2, 150, 70, 0, 100, 200,100]
dPolyline(IMG_Drawing, arrCoordinatesXY2)

Syntax

Building a line point by point Hide the details

dPolyline([<Image>, ] <NbPoint> , <X1> , <Y1> , <X2> , <Y2> [, <Xn> [, <Yn> [, <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.

<NbPoint>: Integer

Number of line segments. This parameter defines the number of <X>, <Y> pairs to specify in the function.

<X1>: Integer

X-coordinate of the first segment of the line. These coordinates are expressed in pixels.

<Y1>: Integer

Y-coordinate of the first segment of the line. These coordinates are expressed in pixels.

<X2>: Integer

X-coordinate of the second segment of the line. These coordinates are expressed in pixels.

<Y2>: Integer

Y-coordinate of the second segment of the line. These coordinates are expressed in pixels.

<Xn>: Optional integer

X-coordinate of the N segment of the line. These coordinates are expressed in pixels.

<Yn>: Optional integer

Y-coordinate of the N segment of the line. These coordinates are expressed in pixels.

<Line color>: Integer or constant (optional)

Line color. This color can correspond to:
an RGB color (returned by RGB),
an HSL color (returned by HSL),
a WLanguage preset 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.

Building a line via an array of X and Y-coordinates Hide the details

dPolyline([<Image>, ] <Array of coordinates> [, <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.

<Array of coordinates>: Array of integers or array of points

WLanguage array of integers containing the coordinates of segments that make up the line. The even indices represent the X-coordinates while the odd indices represent the Y-coordinates of the points. These coordinates are expressed in pixels.

<Line color>: Integer or constant (optional)

Line color. 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.

Building a line using a variable of type Polygon Hide the details

dPolyline([<Image>, ] <Polygon> [, <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.

<Polygon>: Polygon variable

Name of the Polygon variable that describes the different points of the polygon.

<Line color>: Integer or constant (optional)

Line color. 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

Coordinates are specified with respect to the upper-left corner of the image (coordinates: (0.0)).

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 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.

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: wd270pnt.dll