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Bug report: No more blurry images

When you upload an image, we resize it to a number of lower resolutions so that low-resolution devices don't have to download more than they need. However, we failed to make the original version available, which could lead to blurry images. This issue has been fixed.

We have fixed a bug related to images added to text boxes being blurry (pixelated). If you have experienced this issue, you need to remove these images using Calcapp Creator and then upload them once more.

Here’s some background on this issue: Calcapp tries very hard to conserve bandwidth when downloading app images, ensuring that needlessly large images are not downloaded when apps are run. Downloading images in their original resolution would, if the original images were large enough, be time-consuming and waste memory unnecessarily. The end result would be slow and unresponsive apps, especially on low-end cell phones with little memory.

When you upload images through Calcapp Creator, most are resized to a number of lower resolutions. If you upload an image whose largest side is 2970 pixels, this image is resized to the following widths: 200, 400, 600, 800, 1000, 1400, 1800, 2200 and 2600 pixels. If your app is run on a device where the screen is limited to a horizontal resolution of 1080 pixels, a resized image whose width is 1400 pixels is downloaded instead of the original image and is then resized, this time by the app, to a resolution matching the screen. (To achieve this, we use a new-ish HTML5 feature.)

(If your app is running offline, we only store resized versions of your images whose widths measure 1000 pixels or less in order to conserve storage space. As a result, on devices with high-resolution “retina” screens, images may appear slightly pixelated when apps are run offline. We think that is the right tradeoff.)

The problem we had was that we never made the original image, with unmodified dimensions, available for download. For the example image above, with an original width of 2970 pixels, only resolutions with widths less than or equal to 2600 pixels would be made available, not the original image with unmodified dimensions.

For such a high-resolution image, this was a non-issue. There are no widely-available devices with screens with that many horizontal pixels, so the original image would never have been requested.

However, what about an image with a width of 399 pixels? Calcapp would resize the image to a width of 200 pixels and only make that one available, and not the original image. As a result, apps would only display a low-resolution image with a width of 200 pixels. For a square image, that’s a loss of almost three-quarters of the original pixels, making for a particularly blurry image.

To fix this issue, please open your apps in Calcapp Creator, remove all images (or only the images that appear blurry) and upload them again. Problem solved!

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