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  • Limits
  • Coordinates
  • Solid figure
  • Using the drawing functions
  • Drawing in PHP
  • Drawing in Browser code
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Stored procedures
Draws the chord of a circle (intersection between an ellipse and a straight line):
  • in an Image control,
  • in an Image variable.
    WEBDEV - Browser codePHP This type of variable is not available.
  • Versions 25 and later
    WEBDEV - Server code in a WDPic variable (on the background layer),
    New in version 25
    WEBDEV - Server code in a WDPic variable (on the background layer),
    WEBDEV - Server code in a WDPic variable (on the background layer),
  • Versions 25 and later
    WEBDEV - Server code in a picLayer variable.
    New in version 25
    WEBDEV - Server code in a picLayer variable.
    WEBDEV - Server code in a picLayer variable.
Versions 15 and later
WEBDEV - Server codeLinux This function is now available for WEBDEV sites in Linux.
Linux Caution: A specific configuration is required to use this function in Linux. See The drawings for more details.
New in version 15
WEBDEV - Server codeLinux This function is now available for WEBDEV sites in Linux.
Linux Caution: A specific configuration is required to use this function in Linux. See The drawings for more details.
WEBDEV - Server codeLinux This function is now available for WEBDEV sites in Linux.
Linux Caution: A specific configuration is required to use this function in Linux. See The drawings for more details.
Versions 16 and later
WEBDEV - Browser code This function is now available in Browser code.
New in version 16
WEBDEV - Browser code This function is now available in Browser code.
WEBDEV - Browser code This function is now available in Browser code.
// Initialize the drawing in an Image control
dStartDrawing(IMG_Drawing)
// Draw the chord of a circle whose
// background is light yellow and whose border is light blue
dChord(10, 10, 50, 50, 20, 20, 40, 50, LightYellow, LightBlue)
Versions 24 and later
WEBDEV - Server codeAjax
// Draw the chord of a circle whose
// background is light yellow and whose border is light blue
dChord(IMG_Drawing, 10, 10, 50, 50, 20, 20, 40, 50, LightYellow, LightBlue)
New in version 24
WEBDEV - Server codeAjax
// Draw the chord of a circle whose
// background is light yellow and whose border is light blue
dChord(IMG_Drawing, 10, 10, 50, 50, 20, 20, 40, 50, LightYellow, LightBlue)
WEBDEV - Server codeAjax
// Draw the chord of a circle whose
// background is light yellow and whose border is light blue
dChord(IMG_Drawing, 10, 10, 50, 50, 20, 20, 40, 50, LightYellow, LightBlue)
Syntax
dChord([<Image>, ] <X1> , <Y1> , <X2> , <Y2> , <X3> , <Y3> , <X4> , <Y4> [, <Background color> [, <Line color>]])
<Image>: Optional control name or optional Image, WDPic or picLayer variable
Versions 24 and later
WindowsLinux Image to use. This image can correspond to:
  • the name of an Image control.
  • the name of an Image variable.
  • Versions 25 and later
    WEBDEV - Server code the name of a WDPic variable. Only the background layer will be handled.
    New in version 25
    WEBDEV - Server code the name of a WDPic variable. Only the background layer will be handled.
    WEBDEV - Server code the name of a WDPic variable. Only the background layer will be handled.
  • Versions 25 and later
    WEBDEV - Server code the name of an picLayer variable.
    New in version 25
    WEBDEV - Server code the name of an picLayer variable.
    WEBDEV - Server code the name of an picLayer variable.
If this parameter is not specified, it is necessary to define the drawing destination with dStartDrawing.
New in version 24
WindowsLinux Image to use. This image can correspond to:
  • the name of an Image control.
  • the name of an Image variable.
  • Versions 25 and later
    WEBDEV - Server code the name of a WDPic variable. Only the background layer will be handled.
    New in version 25
    WEBDEV - Server code the name of a WDPic variable. Only the background layer will be handled.
    WEBDEV - Server code the name of a WDPic variable. Only the background layer will be handled.
  • Versions 25 and later
    WEBDEV - Server code the name of an picLayer variable.
    New in version 25
    WEBDEV - Server code the name of an picLayer variable.
    WEBDEV - Server code the name of an picLayer variable.
If this parameter is not specified, it is necessary to define the drawing destination with dStartDrawing.
WindowsLinux Image to use. This image can correspond to:
  • the name of an Image control.
  • the name of an Image variable.
  • Versions 25 and later
    WEBDEV - Server code the name of a WDPic variable. Only the background layer will be handled.
    New in version 25
    WEBDEV - Server code the name of a WDPic variable. Only the background layer will be handled.
    WEBDEV - Server code the name of a WDPic variable. Only the background layer will be handled.
  • Versions 25 and later
    WEBDEV - Server code the name of an picLayer variable.
    New in version 25
    WEBDEV - Server code the name of an picLayer variable.
    WEBDEV - Server code the name of an picLayer variable.
If this parameter is not specified, it is necessary to define the drawing destination with dStartDrawing.
<X1>: Integer
X coordinate of top left corner of the rectangle containing the circle. These coordinates are expressed in pixels.
<Y1>: Integer
Y coordinate of top left corner of the rectangle containing the circle. These coordinates are expressed in pixels.
<X2>: Integer
X coordinate of bottom right corner of the rectangle containing the circle. These coordinates are expressed in pixels.
<Y2>: Integer
Y coordinate of bottom right corner of the rectangle containing the circle. These coordinates are expressed in pixels.
<X3>: Integer
X coordinate of start point of the chord. These coordinates are expressed in pixels.
<Y3>: Integer
Y coordinate of start point of the chord. These coordinates are expressed in pixels.
<X4>: Integer
X coordinate of end point of the chord. These coordinates are expressed in pixels.
<Y4>: Integer
Y coordinate of end point of the chord. These coordinates are expressed in pixels.
<Background color>: Integer or constant (optional)
Background color of chord. This color can correspond to:
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)
Line color for the circle chord. This color can correspond to:
If this parameter is not specified, the line color:
  • corresponds to the color specified in the last call to dPen,
  • is identical to the color used for the background if dPen has not been used.
Remarks

Limits

  • dChord is not available in anti-aliasing mode (for more details, see the help about dChangeMode).
  • dChord is not available for a drawing with management of alpha channel (see the help about dStartDrawing for more details). This function has no effect.

Coordinates

If the start and end points are not located on the outline of the circle (or on the outline of the ellipse), the point taken into account is 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).
The coordinates are specified with respect to the top left corner of the Image control (coordinates set to (0,0)).

Solid figure

dChord can only be used to draw a chord: outline only or chord area. To draw a solid figure (portion defined by the center of the circle and the two points on the circle), use dSlice.

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.
  • Versions 24 and later
    WindowsLinux 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.
    New in version 24
    WindowsLinux 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.
    WindowsLinux 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.
PHP

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.
PHP Limitation for dChord: The opacity defined by dBackground is ignored.
Versions 16 and later
WEBDEV - Browser code

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" pane, "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.
New in version 16
WEBDEV - Browser code

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" pane, "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.
WEBDEV - Browser code

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" pane, "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:
The drawing functions 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 : wd250pnt.dll
Minimum version required
  • Version 9
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