I want to fit a picture bigger than 1:1 into square format, but don't want to crop it. How can I do this on iOS?
Your options for resizing the 16:9 image mentioned to be 1:1 in size are
- Crop it
- Letterbox it
- Stretch it
Let's pretend the image is 16x9 instead of 16:9 (units are irrelevant.)
Crop, taking the sides off so that the image becomes "9x9." This is the most obvious way but OP states it is undesirable
Letterbox, place blank space above and below so that it is "16x16." This means that about 46% of the image will be black or white pixels but all image data would be represented in the 1:1 space. In most cases, the end consumer would need to magnify the image to see detail since the 1:1 letterbox displayed on a 16:9 screen would have it's magnification reduced to 56%
Stretch Distort the image such that the pixels are made taller but not wider. your image would be 16x(9*1.77) This would entail making the "scale" of the image 1x1.77. An example of this is when you try to use a 4:3 background as your desktop on a 16:9 screen or vice versa. Good news is that your image will take up the entire 1:1 space. The bad news is that most subjects look very odd when stretched by even a very small amount.
Now that you know the photography terms for what you are trying to do, you can post an appropriate question on iOS SE. Recommending an app is outside the scope of this photo.SE.
I just did a very quick google for "enlarge image canvas ios" and the first result was Photo Canvas Size Increaser.
The 16:9 aspect ratio is almost twice as wide as the 1:1 aspect ratio.
Regular resizing, cropping, letterboxing or stretching is no good.
What you want is to remove the background of an object and shift it over, then crop, preserving the intent of the original image. That's a lot of work, there's got to be an easier way ...
See this video from 2008 explaining that the technique also works for video: "Improved Seam Carving for Video Retargeting", this video: "Using the GIMP Plugin: Liquid-Resizer" shows how it works for photos.
Here's what it looks like:
- 9:16 -> 1:1
- 9:16 -> 16:9
- 16:9 -> 1:1 -- Sometimes it doesn't work out perfectly ...
The reason it didn't work is because there was no seam to carve. Cropping a bit off of the right side would have fixed everything. That's the advantage of using the GIMP Plugin, more control.
For iOS try one of the online applications.