I want to make sure that all the images that users upload to my website are the same size.
The size that I want to achieve is 620px x 405px
Because I don't want any white space in my images, and I want to keep the aspect ratio, I'm guessing I'll need to crop first, before I resize?
So far I've got the following code:
photo.Resize(width: 620, height:405, preserveAspectRatio: false, preventEnlarge: true);
But obviously this isn't giving me the desired affect.
I have seen other articles online where they do some formula, but I can't get any to work for me.
Suppose someone uploads an image which is 1020 wide by 405? Which bit do you want to keep? The left hand end? Right hand end? The middle bit? Then the next image is 3000 x 3000. Now which bit do you want to crop? Perhaps this one needs resizing before cropping otherwise you might only get a window.
My recommendation is to allow the user to specify the crop area, and then you resize the resulting cropped image. There are a number of jQuery plugins that enable client side cropping. I've written about jCrop (http://www.mikesdotnetting.com/Article/161/WebMatrix-Testing-the-WebImage-Helper-With-JCrop) but I have also received some feedback that it is not reliable in some versions of IE (although I haven't tested that myself).
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in our website we are retrieving data from an API, which does not pull images bigger than 100 × 75 pixels, then we show them listed. example We need to double up this size to match with our design.
Is there any Gem that does this, without loosing quality and not impacting performance?
There is no way to upscale an image without losing quality - you're basically asking an algorithm to fill in image data that simply does not exist in the file in the first place.
However, depending on the rate of the scaling and the images themselves, you could have acceptable results.
Since you want to do this effectively and there is no benefit of doing the resizing on the server anyway, I'd advise simply using CSS to achieve this on the client side - just set the desired width/height attributes for the specific img elements.
If you really want to do this on the server (e.g. if you need to save the resulting images), one option would be to use the Paperclip gem's image processing capabilities.
I’m new in iOS and trying to make simple app with hierarchy of viewcontrollers. In the last one I wanna display scrollable image (which can also be zoomed at least x1,5), containing some small black and white picture and a piece of text. Initially I planned to make vector image, convert it to .jpg and use UIScrollView for displaying. But I found out that .jpg ( approx. 150 KB) didn’t provide a good quality for displaying text. As I have to use a lot of images I don’t want to increase image size. What is worse I also want it look good on retina display.
Can you recommend a way how to display image, containing text, with enough quality?
I mean that I don’t want the user see the separate pixels of letters in the text. Just like when you read text in your e-mail in iOS. Image size should be as small as possible. Planning physical size of image – approx. 5 cm x 15 cm.
Any help much appreciated
Thanks
To get good edges you would need to use png not jpg, which will make the image sizes much larger. I have a better suggestion, more code but better solution.
The answer is to not put the text into the image, but to draw it over it in real time.
You would:
associate text at some coordinate in the image (say a CGRect) with the image
create a uiimageview subclass that in the drawRect routine, after calling super, draws the text using the NSString categories on UIKit (which let you draw into a context)
To get going on this please create a small one vc project and get the subclass working there, then back port it to your primary project.
I'll start by explaining what I would like to do.
I have an image gallery grid layout page with thumbnails. Each thumbnail image is to be the same size, say 120px x 80px. I would like to display all the images on page load and more as a user scrolls down on the page. There will be hover and click states for individual images in the grid where the full size image pops up to display in a lightbox.
What solutions (gems, techniques, etc.) are there for loading images that are larger (1024 x 768) into my database (Photo) model such that I can generate a small thumbnail image of predefined smaller size?
Is the best way to load a whole page of small images if my goal is to allow more to load as the user scrolls down on the page? Or should I load only what the user sees, then use AJAX to load more as they scroll down?
Is Paperclip a common solution in this case? I'm looking into this and CarrierWave on RailsCasts.
If using something like Paperclip, can it handle cropping an image that isn't the same aspect ratio as others? ie, scale and crop a square image the same as a rectangle image to a defined size.
I'm new to handling a large number of images in a rails application and appreciate any advice, books, tutorials, techniques people are familiar with out there.
Thanks!
1) I prefer paperclip, though this may be due to less experience with other gems.
2) Generally, the best way to handle lots of images on a page is with sprite sheets. If the images on the page are always going to be the same, this might be a good option. If you are doing something with infinite scrolling, ajax is the way to go (railscast on infinite scrolling)
3) I'm not sure if paperclip is a common solution, but it certainly is one that you should consider.
4) Yes, cropping works in paperclip.
I'm using Tesseract OCR 3.01 in my iOS application, it shows 90% accuracy for my data when I pick an image from my phone’s library. But if I use the same image from the camera, it is showing jumbled letters. I followed this tutorial, kindly guide me if something can be done to make sure it works from camera as it works for gallery images.
Yup, There are three things to be specific, First of all, OCR works well with black and white images rather than colored, So If you could try to convert your image to B&W, it would increase accuracy.
The second thing is the size and orientation, You need to force the image to be of 640*480 or 320 size, this would increase both the speed of recognition and the accuracy as well, For orientation , there are a lot of ways to manage.
Finally, If some how you can allow the user to specify Exactly where or on which part of the image he wants to perform the OCR, this greatly increases the accuracy and time since the library does not need to check the entire image for text, rather you already specify the part to be searched for.
PS:I have been working on creating an OCR app for the past few weeks.
Almost for sure the problem is "orientation". Apple tends to create images in one bit map form - the image bits are laid out as if the camera was on its side with the volume buttons top and right. Images that you see which appear taller than wider are still laid out as above, but there is an "orientation" in the EXIF object included with the image.
I'm going to guess that tesseract does not look at the EXIF, but expects the image in a "standard" format so that text is in the position it would be for a person reading the text.
You can test my hypothesis by using camera images taken with volume button top right.
If they work, then what you will need to do is process the image yourself, and re-arrange the bits per the orientation setting. This is not all that hard to do but will require you to read up on vImage and/or bit map contexts.
I have over 100k in images that at one time were cropped and had a white border applied to them. I'm looking for the best way to programmaticly process each image so that I can detect the white borders and either crop the border or fill in the border with black instead. Would I need to use something like OpenCV or just plain old GDI? I've attached an image for reference.
What I have to work with (White borders are there, trust me):
http://cdn-images.hollywood.com/site/SO_3666231.jpg
Plain old GDI should work just fine, except for one thing - I don't know how to make GDI save an image back to a file. When I've had to do it in the past I've written a .BMP file in pieces, which wouldn't work for a JPEG. Time for a new question?
You're going to need a two step process - first measure the white borders, then copy the image to a new image to get rid of them.
Starting with a JPEG image introduces two small problems. First is that the image will contain some decoding artifacts, and white won't always be an RGB value of (255,255,255). You'll need to establish a threshold, such as (250,250,250) and see how that works; if it doesn't catch all of the borders, you'll need to try a lower threshold. Second is that resaving the image as a JPEG will introduce additional artifacts, lowering the quality of the image. Hopefully this will be within acceptable limits, but only you can be the judge of that.
I'm sorry that this isn't really an answer, perhaps more like 1/4 of an answer. I hope you find it useful.