Hi all,
I'm trying to use the PHP GD functions to make graphical changes to
image files. In particular I'm trying to add a 'highlight' rectangle
to an image. So far everything I've tried doesn't work as I'd expect.
The best I've got is to make a copy of the rectangle and
imagecopymerge( ) it back onto the original with a 'pct' value. This
creates a visible region, but it isn't highlighted, it's always
darker. Here is my code for this:
function highlightSpot($ image, $id, $posx, $posy) {
global $spots;
global $offset;
// get coords of the box to highlight based on $id
$box = spotLegend($ima ge, $id, $posx, $posy);
// get the spot information
$spot = $spots[$id];
// get color index of existing map pixel
// highlight the spot on the map
$rectImage = imagecreatetrue color($spot[3] - $spot[1], $spot[4] -
$spot[2]);
$setpixel = imagesetpixel($ image, 0, 0,
imagecoloralloc ate($rectImage, 0, 0, 0));
$index = imagecolorat($i mage, $spot[1], $spot[2] + $offset);
$rgb = imagecolorsfori ndex($rectImage , $index);
$color = imagecoloralloc ate($rectImage, $rgb["red"], $rgb["green"],
$rgb["blue"]);
// copy section of image to new image
imagecopy($rect Image, $image, 0, 0, $spot[1], $spot[2] + $offset,
imageSX($rectIm age), imageSY($rectIm age));
// merge highlight onto map
imagecopymerge( $image, $rectImage, $spot[1], $spot[2] + $offset, 0,
0, imageSX($rectIm age), imageSY($rectIm age), 80);
imagerectangle( $image, $spot[1], $spot[2] + $offset, $spot[3],
$spot[4] + $offset, imagecoloralloc ate($image, 0, 0, 0));
// clean up
imagedestroy($r ectImage);
}
What I'd really like is to create a highlighted rectangle in yellow,
like someone drew on the image with a 'highlighter'. Any help would be
greatly appreciated.
Thanks,
Doug
I'm trying to use the PHP GD functions to make graphical changes to
image files. In particular I'm trying to add a 'highlight' rectangle
to an image. So far everything I've tried doesn't work as I'd expect.
The best I've got is to make a copy of the rectangle and
imagecopymerge( ) it back onto the original with a 'pct' value. This
creates a visible region, but it isn't highlighted, it's always
darker. Here is my code for this:
function highlightSpot($ image, $id, $posx, $posy) {
global $spots;
global $offset;
// get coords of the box to highlight based on $id
$box = spotLegend($ima ge, $id, $posx, $posy);
// get the spot information
$spot = $spots[$id];
// get color index of existing map pixel
// highlight the spot on the map
$rectImage = imagecreatetrue color($spot[3] - $spot[1], $spot[4] -
$spot[2]);
$setpixel = imagesetpixel($ image, 0, 0,
imagecoloralloc ate($rectImage, 0, 0, 0));
$index = imagecolorat($i mage, $spot[1], $spot[2] + $offset);
$rgb = imagecolorsfori ndex($rectImage , $index);
$color = imagecoloralloc ate($rectImage, $rgb["red"], $rgb["green"],
$rgb["blue"]);
// copy section of image to new image
imagecopy($rect Image, $image, 0, 0, $spot[1], $spot[2] + $offset,
imageSX($rectIm age), imageSY($rectIm age));
// merge highlight onto map
imagecopymerge( $image, $rectImage, $spot[1], $spot[2] + $offset, 0,
0, imageSX($rectIm age), imageSY($rectIm age), 80);
imagerectangle( $image, $spot[1], $spot[2] + $offset, $spot[3],
$spot[4] + $offset, imagecoloralloc ate($image, 0, 0, 0));
// clean up
imagedestroy($r ectImage);
}
What I'd really like is to create a highlighted rectangle in yellow,
like someone drew on the image with a 'highlighter'. Any help would be
greatly appreciated.
Thanks,
Doug