Programming Web Graphics with Perl and GNU Softwar

Name

setStyle( ) — assign a line style to an image

Synopsis

GD::Image::setStyle(@colorindices)

Dotted and dashed lines can be drawn using the GD drawing commands with the gdStyled line style instead of the colorindex parameter. The setStyle( ) method defines a line style for an image. Follow these steps to create a styled line:

1. Allocate the colors you wish to use in the line style, or get their color indices with the colorExact( ) method:

   $blue = $image->colorAllocate(0, 0, 255);    # allocate blue
   $red = $image->colorAllocate(255, 0, 0);     # allocate red

2. Create a list of color indices. Each element of the list represents one pixel in a sequence that will be repeated over the length of the drawn line. To indicate a blank space in a dashed line, use the gdTransparent constant instead of a color index. If a color index has already been marked as transparent for the image, it will also be transparent in the drawn line. To indicate a blue and red dashed line that repeats blue for two pixels, red for three pixels, and then a two-pixel break, use the following for the color list:

   @linestyle = ($blue, $blue, $red, $red, $red, gdTransparent, gdTransparent);

3. Assign the style to the image:

   $image->setStyle(@linestyle);

4. Draw with a drawing method and the gdStyled special color. If the gdStyledBrushed constant is used, the brush pattern will be drawn for those pixels that are not set to gdTransparent. To draw a dashed rectangle, use:

   $image->rectangle(0, 0, 100, 100, gdStyled);

Use setStyle( ) when you need ...