 Basic Tutorial: PHP GD, basic tuts |
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 Oct 24 2004, 12:52 PM
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#1
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death  Group: Members Posts: 268 Joined: 8-September 04 Member No.: 384  |
With php gd is the image function library of php. The functions include in this library enable php users to creating image up to manipulating photos. PHP gd can create with file extension of jpg, gif, swf, tiff and jpeg2000.
Installation see http://www.php.net/manual/en/ref.image.php. Astahost hosting service has enable gd library, so won’t need any extra works except in coding. Lets get started, creating images from php set the canvas: CODE $img = imagecreate(250, 80) imagecreatethis function create and set a blank canvas with the wide of 250 pixels and height of 80 pixels. setting the basic colors: CODE $black = imagecolorallocate($img, 0, 0, 0) $white = imagecolorallocate($img, 255, 255, 255) $red = imagecolorallocate($img, 255, 0, 0) $green = imagecolorallocate($img, 0, 0, 255) imagecolorallocate $img represent the canvas. the next three value is color value in rgb(0-255), you also set the color in hex (0x00 – 0xff). drawing a something: CODE imagerectangle($img, 10, 10, 240, 70, $white) imagerectangle this function create a rectangle a width of 230[240(x2) – 10(x1)] and a height of 60[70(y2) – 10(y1)]. $img the canvas, the first two value sets the starting point(x1, y1) . and last two number is the ending(x2, y2). And the last value is the color. CODE imagefilledrectangle($img, 20, 20, 60, 60, $red) imagefilledrectangle this function create a filled rectangle with a color red. All values is the same as the imagerectangle function. CODE imagefilledellipse($img, 90, 40, 40, 40, $blue) imagefilledellipse this one creates an ellipse(circular objects). $img is the canvas, the first two value(cx, cy) set the origin(center) of the ellipse. The third value set the width(horizontal width) and fifth one is the height(vertical width). Last but not the least the color value. CODE $corners = array( 0 => 190, 1 => 60, 2 => 210, 3 => 20, 4 => 230, 5 => 60, ); imagefilledpolygon($img, $corners, 3, $white); imagefilledellipse and the last drawing function I discuss is a polygon function, in the example there’s only 3 corners. The first value is the canvas, the second one is the corners in array, the value 3 is the number of vertices, and the last one is color. Showing the graphics: CODE header("Content-type: image/jpeg") imagejpeg($img) header imagejpeg To output the image you must first send the appropriate header, in this example I use jpg extension and the content type is set to “image/jpeg”. And call the imagejpeg function to create the images and shown up to the browser. For other file type such as png(image/png), gif(image/gif), windows bitmap(image/vnd.wap.wbmp), check php manual for details. And finally, use the imagedestroy function just to clear up the memory used by the imagecreate functions. Final code should look like this. CODE <?php $img = imagecreate(250,80); $black = imagecolorallocate($img, 0, 0, 0); $white = imagecolorallocate($img, 255, 255, 255); $red = imagecolorallocate($img, 255, 0, 0); $green = imagecolorallocate($img, 0, 255, 0); $blue = imagecolorallocate($img, 0, 0, 255); $corners = array( 0 => 190, 1 => 60, 2 => 210, 3 => 20, 4 => 230, 5 => 60, ); imagerectangle($img, 10, 10, 240, 70, $white); imagefilledrectangle($img, 20, 20, 60, 60, $red); imagefilledellipse($img, 90, 40, 40, 40, $blue); imagefilledellipse($img, 150, 40, 70, 40, $green); imagefilledpolygon($img, $corners, 3, $white); header ("Content-type: image/jpeg"); imagejpeg($img); imagedestroy($img); ?> enjoy  |
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Oct 24 2004, 02:43 PM
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#2
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Member [ Level 1 ]  Group: [HOSTED] Posts: 41 Joined: 12-October 04 Member No.: 1,150 |
Very nice tutorial, well written and very descriptive. I had no clue you could do this with php. I guess you learn something new every day.
Time to go play with this stuff. |
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Oct 24 2004, 04:04 PM
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#3
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Premium Member Group: [HOSTED] Posts: 336 Joined: 22-September 04 Member No.: 798 |
well, to give you an idea what you could use this for: thumbnails
i'm a lazy kid so i upload my pictures with ftp then some guy/girl visits my site and my picture page he opens the directory with the new pictures the script checks all the pictures and checks if they all have a thumbnail (if a filed is called blabla.jpg, the thumb is called .blabla.jpg, so it's invisible too) if there isn't, i make one with gd!!! it's great. i never have to make pages anymore, never make thumbs,... gd rocks quite a lot! |
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Oct 24 2004, 04:28 PM
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#4
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Premium Member Group: [HOSTED] Posts: 336 Joined: 22-September 04 Member No.: 798 |
hm, apearently it's not working atm. it worked before, but today it's all fucked up.
php says it doesn't know the function imagecreatefromjpeg... help! |
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Oct 24 2004, 04:43 PM
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#5
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Newbie [ Level 2 ] Group: Members Posts: 24 Joined: 22-October 04 From: Caracas, Venezuela Member No.: 1,241 |
Maybe the GD library is not enabled...
Wait for tomorrow and see what happends... By the way... I made a picture gallery with PHP+GD... If anyone would like to I can make a tutorial to create thumbnails and stuff... Also an advice: Don't use: CODE imagecreate($width,$height) That could make your pictures look preaty bad... Use: CODE imagecreatetruecolor($width,$height) That makes it look exactly like is and you won't lose the image quality... If you can't use the GD library you could use ImageMagic too.. is a library that can do the same and more... Hope it helps... |
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Oct 24 2004, 05:15 PM
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#6
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Premium Member Group: [HOSTED] Posts: 336 Joined: 22-September 04 Member No.: 798 |
yeah, but all the extensions are disabled atm
gd, exif,... i am using truecolor, don't worry  it works fine on my own computer, but it's not working with astahost. but i've heard/read that they are having problems, so i'll just wait till those are solved... |
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Oct 25 2004, 04:43 AM
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#7
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death Group: Members Posts: 268 Joined: 8-September 04 Member No.: 384 |
outch
 astahost hosting has no gd support for the moment, may be... this is part of the problem . and the tutorial won't work at this time. plz be patient while the admin is fixing this 
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Oct 28 2004, 07:17 PM
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#8
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Advanced Member Group: Members Posts: 160 Joined: 27-October 04 Member No.: 1,260 |
QUOTE(r3d @ Oct 24 2004, 08:52 PM) Final code should look like this. CODE <?php $img = imagecreate(250,80); $black = imagecolorallocate($img, 0, 0, 0); $white = imagecolorallocate($img, 255, 255, 255); $red = imagecolorallocate($img, 255, 0, 0); $green = imagecolorallocate($img, 0, 255, 0); $blue = imagecolorallocate($img, 0, 0, 255); $corners = array( 0 => 190, 1 => 60, 2 => 210, 3 => 20, 4 => 230, 5 => 60, ); imagerectangle($img, 10, 10, 240, 70, $white); imagefilledrectangle($img, 20, 20, 60, 60, $red); imagefilledellipse($img, 90, 40, 40, 40, $blue); imagefilledellipse($img, 150, 40, 70, 40, $green); imagefilledpolygon($img, $corners, 3, $white); header ("Content-type: image/jpeg"); imagejpeg($img); imagedestroy($img); ?> enjoy  Is there a way to save it somewhere on the server as a jpg, gif or png with a filename before imagedestroy($img)? |
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Oct 28 2004, 07:20 PM
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#9
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Advanced Member Group: Members Posts: 160 Joined: 27-October 04 Member No.: 1,260 |
QUOTE(r3d @ Oct 25 2004, 12:43 PM) outch astahost hosting has no gd support for the moment, may be... this is part of the problem . and the tutorial won't work at this time. plz be patient while the admin is fixing this Can we request for it to be installed. gd and magick is fabulous for auto image generation. Freetype is oftenly required too, you will be happy to find out what it can do. |
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Oct 28 2004, 07:33 PM
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#10
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death Group: Members Posts: 268 Joined: 8-September 04 Member No.: 384 |
please don't double post, use the edit button
about the gd it's allready installed. and about your first question no, it must be save as php or it will not be parse, just a suggestion u can do something like this image.php?id=image_name with the gd
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