Where is the small, medium, large, original image functionality from Apple's Mail app?

Question

When sharing an image in an iPhone, we are given an opportunity to pick different sizes of an image - Small, Medium, Large, Original. And an opportunity of see the size in KB/MB along with each classification.

Where does apple expose this code for users to leverage? I couldn't spot it in my searches in iOS docs.
What are some tested & tried frameworks/methods available on GitHub or elsewhere that can emulate this behavior?

EDITED: I evaluated the solution posted by Brad Larson: UIImage: Resize, then Crop By confirming a decrease in size via the size measuring solution given below. Together they are a good fit.

@Kashiv please don't change the intended title of the question. — pulkitsinghal, Feb 13 '12 at 17:49
Sorry, I thought you were asking specifically about compression — akashivskyy, Feb 13 '12 at 18:11
2012-02-22 00:24:24.130 took a picture.................. 2012-02-22 00:24:24.136 Original 2592x1936 (19.14 MB)... 2012-02-22 00:24:24.300 Original 100x100 (0.04 MB)...... — pulkitsinghal, Feb 22 '12 at 06:28

score 1 · Accepted Answer · edited Feb 22 '12 at 06:22

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Where does apple expose this code for users to leverage? I couldn't spot it in my searches in iOS docs.

iOS is not open-source project. Apple releases only sample code which is used like tutorial sample project.

Here's an article regarding calcutation of image file size.

This is very simple, though. Here's the code:

UIImage *image = [UIImage imageNamed:@"your_big_image.png"];

size_t depth = CGImageGetBitsPerPixel(image.CGImage);
size_t width = CGImageGetWidth(image.CGImage);
size_t height = CGImageGetHeight(image.CGImage);

double bytes = ((double)width * (double)height * (double)depth) / 8.0;

Now you have your image size in bytes.

To convert it to kB divide it by 1024. If you want to get MB, divide by 1048576 (1024x1024).

double kb = bytes / 1024.0f;
double mb = bytes / 1048576.0f

Then you can display it to your user by formatting your message as following:

NSString *msg = [NSString stringWithFormat:@"Original %dx%d (%.2f MB)", (int)width,(int)height, (float)mb];

edited Feb 22 '12 at 06:22

bneely

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answered Feb 13 '12 at 15:56

akashivskyy

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You mean how to compress image or how to read if it's compressed? – akashivskyy Feb 13 '12 at 16:13
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I mean, how to calculate the target size of the compressed image, without scaling and compressing it first. – JustSid Feb 13 '12 at 16:33
The image size was an example, my actual question is: Do you know if Apple happens to expose their implementation for compressing images or not? :) – pulkitsinghal Feb 13 '12 at 17:44
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@pulkitsinghal And the answer is no. – JustSid Feb 13 '12 at 17:51
Works well when combined with and used to validate Brad Larson's solution for compression & scaling provided here: http://stackoverflow.com/questions/603907/uiimage-resize-then-crop – pulkitsinghal Feb 22 '12 at 06:26

Where is the small, medium, large, original image functionality from Apple's Mail app?

1 Answers1