dPolyline (Function)

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dPolyline (Function)

In french: dPolyligne

Draws a line composed of several segments. 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 variable

Image to use. This image can correspond to:
the name of an Image control.
the name of an Image variable.
This type of variable is not available.
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 corresponds to:
an RGB color (returned by RGB),
an HSL color (returned by HSL),
a preset color of WLanguage.
If this parameter is not specified, the line color:
corresponds to the color specified during the last call to dPen,
is identical to the color used for the background if dPen was not 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 variable

Image to use. This image can correspond to:
the name of an Image control.
the name of an Image variable.
This type of variable is not available.
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 subscript represent the X coordinates while the odd subscripts represent the Y coordinates of points. These coordinates are expressed in pixels.

<Line color>: Integer or constant (optional)

Line color. This color corresponds to:
an RGB color (returned by RGB),
an HSL color (returned by HSL),
a preset color of WLanguage,
a Color variable.
If this parameter is not specified, the line color:
corresponds to the color specified during the last call to dPen,
is identical to the color used for the background if dPen was not used.

Remarks

Coordinates

The coordinates are specified in relation to the top left corner of Image control (coordinates set to (0,0)).

Using the drawing functions

The drawing functions can be used according to 2 methods:

Method 1: Using dDrawing
- dStartDrawing must be called before any other drawing function. dStartDrawing is used to define the element (Image control or Image variable) onto 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.
Versions 24 and later
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.
New in version 24
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.
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.

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 : wd240pnt.dll