I would like to create PNG images using PHP on a website. These shall be printed at a defined scale. So I would like to set the DPI value of the images using PHP directly. Unfortunately I did not find any function call for this.
Is there any function that can set/update metadata of PNG files?
Maybe an other solution is more reasonable as using a HTML-Wrapper with CSS style sheet for printing which externally defines the resolution. But I would prefer the "directly on the image" approach...
PNGs can contain arbitrary headers. If you look at the PNG specification, you can add tEXt blocks (which are called chunks) to a given PNG. See section 4.2.3 of the specification for more information on tEXT chunks.
As an example, Adobe Photoshop adds meta XML to its PNGs. I'm not sure if GD supports this, but I'd look there to start. It's definitely possible.
Here is some PHP code that deals with parsing PNG chunks. It might steer you in the right direction. http://code.svn.wordpress.org/imagelibs/libpng.php
Here's an screenshot for a text editor of a PNG, showing the XML that was generated by Photoshop. https://stackoverflow.com/a/14356339/278976
THe pHYs chunk (Physical resolution) lets you set a DPI (well, actually pixels by meter, but it's just a unit conversion). Of course, the PNG reader might ignore it.
PHP does not include (AFAIK) support for reading/writing full PNG metadata, you must do it yourself, see eg
The easiest way is to use ImageMagick, as suggested in this answer. If You want to set PNG resolution in pure PHP, you may look at my answer to the similar question.
Related
I am using HTML2PDF converter in order to export web page to PDF file. The issue I have faced is that the result PDF is to large (more than 1 MB). I want to reduce it, so here is what I have basically:
2 images (100 KB both)
1 Courier Bulgarian font - added
3 tables with a lot of inline styles of each cell
Could these things lead to the large size of the output PDF? And could anyone share some experience and best practices with the library in order to get smaller PDF as result.
Thanks in advance.
If you have access to Adobe Acrobat, it'll let you peek in the PDF and see which areas use what percentage of space. This would tell you how much of the space is taken up by images, fonts etc... If you make a sample PDF available I'll be happy to take a look at it.
How much space in the PDF is used by different objects really depends on how the PDF was written and how efficiently it uses different compression algorithms. For example, images can be ZIP, JPEG or even JPEG-2000 compressed in PDF, the question is what HTML2PDF does with your images.
Fonts can be big as well - depending on what the size of the original font is.
Page content (your tables with inline styles etc) are written in a condensed textual format (for example 1 0 0 rg would be the instruction to set the fill color for text and line-art to red). Normally efficient PDF writers will write all of these textual instructions and then ZIP compress them, which means they won't take much place in the file.
So you'd really need to take a look at the PDF file itself to see where the space is used. That will allow you to start looking at the library to see if it can be made more efficient.
To start with...
Have one separate page for printing and displaying - for printing.
While printing use Ptint.CSS and include as less as possible classes
In those three tables. Keep only require classes in CSS. Please use compress images for printing e.g if you have BMP in display use the PNG for printing.
Make tables simple using TR-TD and make them less colorfull do not put inline CSS.
This may help you to save PDF in compress version.
I have mananged to find what causes the big size of my output PDFs files. It last the fonts.
For my task I have used courier bulgarian (italics, normal and bold). This means I have embeded three additional fonts.
Something more, I do not know, but helvica is the defauld font for this PHP library and althought I am not using it, it is embeded to the PDFs too.
If you meet the same issue, open all files that have "helvica" and replace the "helvica" font with this that you are using.
Lot of user opening my site in mobile,
Tell me which image type will load quickly in mobile device ,
jpg,gif,png ,
Which one is best ?
Go with PNG8 where possible and limit the color palette. Try to only use as many colors as strictly needed not more.
There are PNG tweaking tools which allow you to get rid of unnecessary chunks of that PNG. For more information on PNG chunks there is the PNG chunks specification found here.
http://www.libpng.org/pub/png/spec/1.2/PNG-Chunks.html
The tweaking tool I was talking about can be found here. It runs on Linux using wine as far as I have tested it.
http://entropymine.com/jason/tweakpng/
Additionally TinySVG is a pretty interesting format. SVG graphics allow lossless rescaling and because it is in fact a XML file you can modify it in a programmatic way.
EDIT: One note on JPEG graphics. If the file size exceeds 10kb save it progressive if it is under 10bk save it baseline. It is a small optimization for JPEGs.
There is no single "best" image type. The image that loads the quickest is the smallest one. But quick loading does you no good if your image is distorted and unidentifiable.
Pick image format base on the type of image you are trying to render:
JPEG is hands down the best for photos 99% of the time when you consider perceived image quality relative to file size; but JPEG's lossy compression algorithm relies on the existence of noise (lots of soft/subtle color transitions) and a lack of sharp lines/edges in the source image for the best effect. Never use JPEG for rasterized text!
PNG is the best option for rasterized images comprised of sharp edges and smooth/solid color blocks. Basically, anytime you need clean/lossless images (logos, icons, UI elements, text, etc.—anything but photos/paintings basically), you'd use PNG. It is also the only real option when you need alpha channel/partial transparency.
GIF is the only universally support animated image format, but aside from that I would just use PNG in most cases.
SVG is for vector images, but I'm not sure how many mobile browsers support it.
From a quick read, it seems that jpeg would be the best option. However, that is dependent on any specific needs you may have for some images (ie jpeg does not do transparent backgrounds, etc.)
Also, especially for a mobile site, if the images are frequently used parts of the website's layout (ie buttons, etc.) then using CSS Sprites is a good practice as it reduces the number of elements being downloaded to the user (of course, at the tradeoff that the image(s) which are downloaded are larger).
I am working on a website in which the client wishes to have users upload background images to a printable design, crop to size, add text. Do this to multiple pages then generate a pdf of the 'book'
I am running into the following issues/questions and just need to see where I can start
Are there any PHP developer packages that can do something similar. I have seen jquery crop tools but something also for adding text to an image?
How would I keep the resolution up? If the final cropped with text image needs to be 150dpi, when cropping I am guessing I would have them working on a 72dpi image, then somehow apply the crop and changes to the large image?
If the resolution issue wasn't a big deal I would go about it this way:
Simple image upload
Use jquery to crop photo to correct dimensions
Mess around with gdlibrary and imagettftext() to get the text onto an image (page)
Use something like FPDF to create a pdf from each 'page'
Is this the right way to go about it and any thoughts on the resolution issue. Thank you for any help!
Your primary tool should be ImageMagick. ImageMagick can do the cropping, resizing, scaling, overlay text or graphics, combining images, and apply special effects. A big advantage of using a separate tool instead of PHP's image manipulation tools is that you can do the same transforms in batch through other mechanisms, or even hand the work over to another server to keep the website more responsive. And if you do want to integrate it tightly into the website, you can use the MagickWand For PHP interface.
Cropping does not change DPI, only the dimensions of the image. Scaling, on the other hand, changed both.
You should take a look at Gallery, a GPLed program with some of the functionality you're looking for, and written in PHP.
domPDF is a good tool for converting HTML to a PDF. this way you can use the image they upload as a background image, then put the text over it in any standard HTML tag.
As far as the resolution/dpi issue goes, I'm not sure if there is much you can do outside of changing the size of the image. I would recommend looking into This PHP Library, which has a lot of good tools for manipulating images.
I think with a combination of these tools, you'll be able to create HTML that can make a PDF that's fit to print, and use that.
On my site I have given an option to user to choose thier profile image
Type link of an image
Image is a url link, and first I want it to resize to 400x300 (image's original size doesn't matter), and then display it on my web page.
Something like below:
<img src="http://mywebsite.com/resize.php?image=http://someotherurl.com/upload/image2.jpg&width=400&height=300" />
anyone knows this kind of script, please tell me how to solve this issue.
Thanks
A recent post:
https://stackoverflow.com/questions/1302464/php-image-resize-my-upload-script
has some code and comments that may give you some pointers. Otherwise may I suggest
http://www.white-hat-web-design.co.uk/articles/php-image-resizing.php.
Good luck!
If you have the GD extenstion, you can use imagecopyresampled (the documentation also features some examples). However, if the image to be resized is large and there is a low memory limit on your server, you may run out of memory.
I don't have ready to use source code, but it should look like:
Load image pointed by image parameter into object of ImageMagick (or other graphics library).
Resize it.
Send content to output stream.
Optionally you could:
Check if loaded file is image (plus other validation checks).
Save resized image on disk and serve it from disk next time (if you do it often).
Check docs of you favorite graphics library used in PHP for details.
Good luck!
Use the Class called - class.upload.php.
Find it at: PHP Classes
We use it at all times in many of our work.
The name is deceptive but actually it is an uploader as well as image processor. It has a very big list of functionality for resizing images, adding text to images, converting formats, etc. etc.
There is sample code which shows how to read an Image from server, modify it and finally send it directly to browser without having to create a temp file on server.
HTH
How can I rotate a pdf document using php and linux?
Rotate an Entire PDF Document's Pages to 180 Degrees
$command = "pdftk in.pdf cat 1-endS output out.pdf";
system($command);
You could use pdf90 from PDFjam.
To address some of the other suggestions:
I would be wary of adjusting the Rotate attribute directly, as this attribute is stored as text, and '90' or '270' obviously uses a different number of bytes to '0'. I believe inserting the required bytes can make a mess of the index tables that appear at the end of a PDF file. After that, you're reliant on a viewer being able to interpret the damaged file.
Rendering the PDF to an image and rotating that is going to rasterize any text or vector graphics, leading to either a much larger file size, or much lower quality.
You would have to use a external library like this to extract the info a generate an image, then put it back to the pdf(or a new one)
EDIT:
If your going to get a Logo or a diagram this is a good choice, if its a big document with text and lots of images... its going to be pretty hard, could you edit the OP with more info on what you need?
You will have to access the PDF as a binary file then find and adjust the "Rotate" attribute for each page (and possibly the "MediaBox" attribute). I am not aware of any PDF libraries for PHP that allow for this sort of direct manipulation of existing files. This method will not require changing anything about the content of the pages, it just changes the orientation the pages are displayed in by viewers (similar to the EXIF Orientation information in JPEG images).
This snippet of perl should help illustrate what parts of the file you are looking for.
There are a few libraries for handling PDFs with PHP.
Here's a good code example using such a library. I found it, just by Googling "PHP PDF":
http://www.fpdf.org/en/script/script2.php