I would like to rotate an image (with a user-defined angle of rotation), but without making the image smaller.
is what happens already, saving the shaded area as a smaller image
is what I would like, the dashed line being the new image size.
The server has PHP 5.3+. Links, code and explanations all very welcome.
This is not complete answer but I would take the four corners as coordinates rotate them by your angle and then calculate the new bounding box based on the extent of the new coordinates.
(assuming coordinates with origin on the bottom left).
corners = rotate_each ( [(left,top) (left,bottom), (right,top), (right,bottom)], angle)
new_bb_left = min([corners[0].x, corners[1].x, corners[2].x, corners[3].x])
new_bb_right = max([corners[0].x, corners[1].x, corners[2].x, corners[3].x])
new_bb_bottom = min([corners[0].y, corners[1].y, corners[2].y, corners[3].y])
new_bb_top = max([corners[0].y, corners[1].y, corners[2].y, corners[3].y])
This could be a way to do it. Calculate the diagonal width.
PHP has a Square root function: http://se2.php.net/manual/en/function.sqrt.php
In that way you should have the diagonal width which you could apply on the transformed image.
There are many solutions including the trigonometric formulas but this library seems to be the shortcut.
http://wideimage.sourceforge.net/
Example: http://wideimage.sourceforge.net/wp-content/current/demo/index.php?demo=rotate&output=preset%20for%20demo&colors=255&dither=1&match_palette=1
Related
Lets say I have an arrays of pixels. Basically an array of this data {x,y,r,g,b,a} for each pixel.
How would I go about converting all this data into an actual image file (png preferably)?
Could not find a solution. Any help would be very appreciated.
I had some time to code up a little example. You should be able to see and note that:
the red component increases towards the bottom of the image
the green component increases towards the right of the image
the blue component is absent
the alpha channel is random and between 0 (opaque) and 127 (fully transparent)
// Define width and height
$w=800;
$h=600;
// Create truecolour image so we can have infinitely many colours rather than a limited palette
$img=imagecreatetruecolor($w,$h);
imagesavealpha($img,true);
imagealphablending($img,false);
// Iterate over all pixels
for($y=0;$y<$h;$y++){
for($x=0;$x<$w;$x++){
$r = round(255*$y/$h);
$g = round(255*$x/$w);
$b = 0;
$alpha = rand(0,127);
$color = imagecolorallocatealpha($img,$r,$g,$b,$alpha);
imagesetpixel($img,$x,$y,$color);
}
}
// Save result
imagepng($img,"result.png");
I'll admit I haven't actually used this API, but looks like PHP has what you're looking for.
You create an image identifier with imagecreate or one of the related functions, then color in each pixel with imagesetpixel, using a color identifier created with imagecolorallocatealpha. From there you should be able to output as a PNG with imagepng.
It's worth noting that this image library seems to support drawing lines and shapes and other structures higher than the per-pixel level, so I'd also look into whether your code necessarily needs to build a big pixel array, rather than drawing the image some other way.
I did found a topic similar to this, but I do not know if the solution is the same. So here is my question:
I'm using the GD functions to bild a web card generating program. The thing is that the card's backgound is generating by the $image = imagecreatefrompng(); function.
The card need's also a $cardname as "title" and a $desription as desription. For that I used the imagettftext(); function. But there is a problem, the card's size is 333x485, I need the text to be resized in order to fit in the background without resizing its height, but only the width!
To be more to the point, the $cardname should have width = 240 and height = 34, but if it doesn't fit, it goes off the background, I need a function that will resize its width in order to fit in 240px and leave the height to 34px always!
To understand it more look here: http://yugiohcardmaker.net. in the "name" you can add as much text you like, it will always fit in and in the right width and height!
I'm not going to try and code this as it will take too long, but here's the basic process:
Get the size of the bounding box for your text with imagettfbbox();
Create a new image with imagecreatetruecolor();
Write your text into your new image with imagettftext();
Use imagecopyresampled() to copy the new image with your text to your existing card, setting the parameters to shrink the width but not the height.
Note: the bounding box parameters returned by imagettfbbox()) can be fiddly to work with
You'll also need to be careful about alphablending and background colors to ensure that only your text pixels are copied.
Good luck!
I'm using php Imagick class for a project
I try to composite an image changing the gravity of the image
What I mean is, I want to composite the target image to middle or to the top center
I use
....
$imageOrg->setGravity(imagick::GRAVITY_CENTER); //I wrote this for an example, position will be set by the visitor
$imageOrg->compositeImage($over, Imagick::COMPOSITE_DEFAULT, 0, 0);
....
But either setGravity() or setImageGravity() functions don't work.
Please help!
$imageOrg->compositeImage($over, Imagick::COMPOSITE_DEFAULT, (((($imageOrg->getImageWidth()) - ($over->getImageWidth())))/2), (((($imageOrg->getImageHeight()) - ($over->getImageHeight())))/2));
Basically what you're doing is setting the left offset of your image to your Container's width, minus your composite image's width, divided by two, this will offset it enough to center horizontally. Then you do the exact same thing for the height, and it's centered vertically.
I had the same type of problem, best I can figure Gravity settings only apply to Drawing contexts, ie: Text, annotations
Hi all
i am displaying an image in a div and content in another div.using jquery draggable method, i placed the content in that div on the image. Now i want to save that image with content as an image. Is it possible? please answer this as it is important
It's perfectly possible to do this, but it's not trivial and I won't post all the code necessary to do it. Instead, I'll give you some pointers:
You can't save the added text "as is" client-side. That's not possible. You could take a screenshot of it, but that's probably not what you want.
Instead, you need to save the text value and the position and size of where the text is placed relative to the image.
Use relative values, e.g. x = 0.3242, y = 0.5123, width = 0.5123, height = 0.12, where x = 0, y = 0 is the top left corner of the image and x = 1, y = 1 the bottom right corner, width and height similarily representing a fraction of the image size.
POST this information to the server and recreate the same effect by baking the text into the image using, for example, gd.
For finding the right font size to use, futz around with imagettfbbox until you have found the closest equivalent in size to the target coordinates.
Use imagettftext for writing the text into the image.
Would like to turn this into black and white.. can't figure out what to use from imagick..
$handle_data = file_get_contents('http://www.bungie.net/Stats/Reach/Nightmap.ashx');
//http://www.bungie.net/Stats/Halo3/Nightmap.ashx
$img = new Imagick();
$img->readImageBlob($handle_data);
$img->writeImage('nightmap/'.$time.'.gif');
Using Imagick::modulateImage could be a quick&dirty solution. Dirty because color theory is a rather complex field, and there can be done more to create grayscale images than just desaturating the image (like applying different weights to the single color channels).
bool Imagick::modulateImage (float $brightness , float $saturation , float $hue)
Given an image, keep brightness and hue at 100%, while setting saturation to 0%. There is an example at the bottom of the documentation page that does exactly that.
There's a much better (and just as simple) solution: $im = $im->fxImage('intensity');
That applies a function to the image, where intensity is equal to 0.299*red+0.587*green+0.114*blue.
That formula is based on how our eyes are more sensitive to different colours, and as such the difference between that and a "flat" grayscale image really is night and day.
More details here:
http://php.net/manual/en/imagick.fximage.php
http://www.imagemagick.org/script/fx.php