There have been many desktop applications about viewing images but I was just not able find a single one that supports touch well. Although Windows 10's "Photos" app support touch, many users do not like it for many reasons. We can see a lot of 1 star reviews for the "Photos" app but there are not good alternatives in Windows Store.
What it does
View various kinds of pictures, including .psd, tga, dds, and most of the raw files that the default "Photos" app cannot open. Easy operations with both mouse and touch. Very fast loading. Can stop a gif or magnifying animate gif files by each frame.
How I built it
This needs a lot of low level coding using C++. The gestures by touch need to be recognized with complicated algorithms.
Challenges I ran into
Since it is on PC/tables, it needs to support both touch and mouse well, I have to do a lot of low level interaction detection.
Accomplishments that I'm proud of
many kinds file format support easy an intuitive operation support for mouse and touch great support for gif animated pictures
What I learned
It is no easy task to design a photo viewer. It is actually much more difficult than a light image editing tool.
What's next for 123 Photo Viewer
Now the app has already got more than 200,000 user in Windows Store. The next target is 1 million users.
touch experience support added after March 15 for this existing app
Before March 15, the touch experience was not supported well and some important touch experiences were not supported at all. Before March 15, sliding of thumbnails with inertia was not supported; sliding with XAML slider in the thumbnail view was not supported; the sliding of images in normal view was weird and full of bugs; sliding of folders after we add a lot of folders was not supported, and the sliding in full screen image viewer mode was not supported either. Basically earlier the support for touch experience was really bad. With a lot of improvements and bug fixes from low level with native C++ coding for gesture recognition, the touch experience is now roughly as good as mouse.