imagealphablending(3) [php man page]

IMAGEALPHABLENDING(3)							 1						     IMAGEALPHABLENDING(3)

imagealphablending - Set the blending mode for an image

SYNOPSIS

       bool imagealphablending (resource  $image, bool	$blendmode)

DESCRIPTION

       imagealphablending(3)  allows  for two different modes of drawing on truecolor images. In blending mode, the alpha channel component of the
       color supplied to all drawing function, such as imagesetpixel(3) determines how much of the underlying color should  be	allowed  to  shine
       through.  As a result, gd automatically blends the existing color at that point with the drawing color, and stores the result in the image.
       The resulting pixel is opaque. In non-blending mode, the drawing color is copied literally with its alpha  channel  information,  replacing
       the destination pixel. Blending mode is not available when drawing on palette images.

PARAMETERS

	      o $
		image -An image resource, returned by one of the image creation functions, such as imagecreatetruecolor(3).

	      o $blendmode
		- Whether to enable the blending mode or not. On true color images the default value is TRUE otherwise the default value is FALSE

RETURN VALUES

	Returns TRUE on success or FALSE on failure.

EXAMPLES

       Example #1

	      imagealphablending(3) usage example

	      <?php
	      // Create image
	      $im = imagecreatetruecolor(100, 100);

	      // Set alphablending to on
	      imagealphablending($im, true);

	      // Draw a square
	      imagefilledrectangle($im, 30, 30, 70, 70, imagecolorallocate($im, 255, 0, 0));

	      // Output
	      header('Content-type: image/png');

	      imagepng($im);
	      imagedestroy($im);
	      ?>

NOTES

       Note

	      This function requires GD 2.0.1 or later (2.0.28 or later is recommended).

PHP Documentation Group 												     IMAGEALPHABLENDING(3)

IMAGETRUECOLORTOPALETTE(3)						 1						IMAGETRUECOLORTOPALETTE(3)

imagetruecolortopalette - Convert a true color image to a palette image

SYNOPSIS

       bool imagetruecolortopalette (resource  $image, bool  $dither, int  $ncolors)

DESCRIPTION

       imagetruecolortopalette(3) converts a truecolor image to a palette image. The code for this function was originally drawn from the Indepen-
       dent JPEG Group library code, which is excellent. The code has been modified to preserve as much alpha channel information as  possible	in
       the  resulting  palette,  in addition to preserving colors as well as possible. This does not work as well as might be hoped. It is usually
       best to simply produce a truecolor output image instead, which guarantees the highest output quality.

PARAMETERS

	      o $
		image -An image resource, returned by one of the image creation functions, such as imagecreatetruecolor(3).

	      o $dither
		- Indicates if the image should be dithered - if it is TRUE then dithering will be used which will result in a more speckled image
		but with better color approximation.

	      o $ncolors
		- Sets the maximum number of colors that should be retained in the palette.

RETURN VALUES

	Returns TRUE on success or FALSE on failure.

EXAMPLES

       Example #1

	      Converting a true color image to a palette-based image

	      <?php
	      // Create a new true color image
	      $im = imagecreatetruecolor(100, 100);

	      // Convert to palette-based with no dithering and 255 colors
	      imagetruecolortopalette($im, false, 255);

	      // Save the image
	      imagepng($im, './paletteimage.png');
	      imagedestroy($im);
	      ?>

NOTES

       Note

	      This function requires GD 2.0.1 or later (2.0.28 or later is recommended).

PHP Documentation Group 												IMAGETRUECOLORTOPALETTE(3)