I want to intercept the imageresizing.net pipeline to conditionally resize an image. The scenario is this.
Any image 600px or larger should be resized down to 600px wide
if an image is 300-> 599px it should be resized to 300px wide
if its less than 150px it should be padded with whitespace to 300px wide.
I know i can achieve each of the above using the library but i don't know in advance of making the call the size of the source image. Is there an entry point where i can intercept the original image size and adjust the resize criteria as above?
I did find this but I'm not certain exactly how to implement it. How to avoid imageresizing if width and height is same as original?
To accomplish this in an efficient manner, you would have to store the source file width/height somewhere fast. Opening the source file each time isn't acceptable.
Related
I have two images I want to combine together with image magick. The way I have it setup right now is a form will upload an image to a server, resize the image to make a smaller version, then save both to a folder. I have my code setup correctly for this using image magick and it works just fine.
What I'm looking to accomplish is sort of like annotating it, however I'd like to do this by appending a header image to the top of the file. I know I can accomplish this using the -append flag. What I'm confused on is how I can match the image sizes so I don't need to do several resizes.
I'm making the resizing occur only if the uploaded files exceed 1000x1000 (using the -resize 1000x1000> argument), but this doesn't guarantee that all files will be 1000px wide. I've made the header image 1000 pixels wide, and when the image is at 1000px, appending those is no problem.
My problem is deciphering how it should be handled when it's smaller than that. Do I resize the header image to the other images size, then append? I know it'd be better to avoid scaling the image up to 1000px, then appending the header and scaling back down, as that would affect image quality. Can I resize the header image without writing it to a temporary file? Like, chain the events and only end up writing a single completed file to disk?
I'm working with documents, so maintaining the the original image dimensions and subsequent dpi is important.
The aspect ratio is always maintained so the automatic fill modes and alike don't seem to have any effect.
Say I have a 300 dpi document and the user want to clear an inch border around the image. So I need an inch cropped from the image but the result needs to be the original image dimensions (2550x3300).
I have been able to achieve this effect with...
...&crop=300,300,-300,-300&margin=300,300,300,300
This works, but seems more than a little clunky. I've tried a lot of other combinations but they all seem to enlarge or reduce the image size which is undesirable in my case.
So does someone know a simpler syntax to achieve the desired result, or do I need to re-size the image then calculate and fill with a margin as I'm doing now.
Thanks
It turns out that my example requests the image in it's full size which turns out to be a special case. When I introduce a width or height into the command line things don't work very well since crop size is in respect to the original image dimensions and margin size is in respect to the result image.
Thinking about it more I abandoned the crop approach. What I really needed was a way to introduce a clipping region into the result bitmap. So I built an extension to do just that. It works well as it doesn't interfere with any of Resizer's layout calculations and the size of the returned image is whatever the height or width were specified as. Which is just what I needed. The Faces plugin has an example of introducing a clipping region.
Karlton
Cropping and re-adding 300px on each edge is best accomplished exactly the way you're doing it:
&crop=300,300,-300,-300&margin=300
What kind of improved syntax would you expect? This isn't a common operation.
How does Safari determine what size to output an svg in the following scenario;
SVG code
viewBox 0 0 800 800
height 100%
width 100%
css
svg width 100%
containing div width 60%
Safari outputs a much smaller svg than the 60% of screen, ok this is a bug. But what determines the size of this smaller svg, it has no connection to anything I can think of.
Just to give some background info. Safari needs both width and height in px for it to do what you want. % don-t work. But it does output the svg, and so it must make a decision somewhere about its size.
It's not a bug you're seeing. That's the correct behavior. The browser by default scales the SVG viewbox (careful with the terminology now, we're not talking about the browser viewport) to fill the CSS-determined dimensions of the SVG element. The fill behavior is determined by the SVG preserveAspectRatio attribute. By default it's set to meet, which keeps the whole SVG viewable, and the aspect ratio preserved. The alternative is slice which scales the viewbox up to cover the element, even when that means cropping. (slice behaves similarly to background-size:cover in CSS3.)
What you need to do is:
a) Don't declare explicit height or width in the SVG file. If your graphics editor is generating them, just go in by hand and delete them. According to the spec, if no width and height are specified, a value of 100% is assumed, so your pseudocode is redundant at best.
b) Make sure you're setting an explicit height for the svg element in CSS. I recommend developer or Canary builds of Chrome for troubleshooting responsive svg sizing, as there is a bug in Chrome 18 Dev Tools that has since been fixed. Once you've got it working in Chrome, it will almost certainly also work in Safari.
c) Figure out how you want to set preserveAspectRatio and manually edit the svg to put in the declaration.
If you're still having trouble, please post a jsfiddle. It's much easier for other people to comment on.
I have been looking for the solution on the web for a long time. Most tutorials are fairly simple about adding shadow to a UIView. I also noticed that if we add a shadow to an UIImageView. The shadow shape could perfectly fit the shape of the content image if the image itself has alpha channel in it. Say for example, if the image is an animal with transparent background, the shadow shape is also the same as that animal (not a rectangle shadow as same as UIImageView frame).
But these are not enough. What I need to do is to add some changes to the shadow so it may have some rotation angle and compressed (squeezed or shift) effect so that looks like the sunlight comes from a certain spot.
To demonstrate what I need, I upload 2 images below, which I captured from the Google Map App created by Apple. You can imagine the Annotation Pin is an image which has the Pin shape, so the shadow is also "pin shaped", but it is not simply "offset" with a CGSize, you can see the top of the shadow is shifted right about 35 degrees and slightly squeezed the height.
When we tap and hold and pin, the shadow is also animated away from the pin, so I believe that such shadow can be made programmably.
The best shadow tutorial I can found so far is http://nachbaur.com/blog/fun-shadow-effects-using-custom-calayer-shadowpaths But unfortunately, that cannot make this effect.
If anyone know the answer or know any better words to search for, please let me know. Thank you.
(Please note that the shape of the image is dynamic in the App, so using any tool like Photoshop to pre-render the shadow is not an option.)
In order to create dynamic effects like this, you have to use Core Graphics. It's incredibly powerful once you know how to use it. Basically you need to set a skew transform on the context, set up a shadow and draw the image. You will probably have to use transparency layers as well.
It doesn't sound like you can use CALayer shadows, since that is meant to solve a specific use-case. The approach Apple takes with the pin marks on the map is to have two separate images that are created ahead of time (e.g. in Photoshop) and they position them within the map relative to a reference point.
If you really do need to do this at run-time, it should still be possible by using either Core Graphics or ImageKit. To get a blurred shadow appearance, you can use the kCICategoryBlur CIFilter. You can then convert the image to grayscale. And to get that compressed look you just need to resize and skew the image.
Once you have two separate images, you can either take the CGImageRef for the shadow image and can set that as the content of another sublayer, or you can add it as a separate view.
If you know what all the shapes are, you could just render a shadow image in Photoshop or something.
My app downloads images from a website. These images are all manner of sizes, from 800x600 up to 1800x1600. I analyze the image using facial recognition, and then want to resize and crop the image. However, it's important that the detected CGRect be visible on the cropped image.
I was using the excellent UIImage+Resize code and using UIViewContentModeScaleAspectFill, but it doesn't seem to have a programatic way of specifying an arbitrary location that needs to be visible in the final image. So if a face is located at the 1600px range of an 1800x1600 image, it'll get cut off.
Is there an easy solution to this, or do I need to dig around in the depths of UIImage+Resize? Any guidance would be appreciated!