About

It is a simple and lightweight drawing application that supports input from external devices such as graphics tablets. Classic touch input with pressure emulation is also implemented (currently in separate driverless branch).

Android 5.0.1

Android 4.2

System requirements

The application stack was selected in such a way that it works even on very old devices with Android 3.1 (the minimum version that supports both OpenGL ES 2.0 and Usb OTG connection). Tested on Android 4.2, Android 5.0.1, Android 6.0, Android 12. The size of the final package (.apk) is currently 58 kilobytes (including icons). The maximum graphics buffer size is about 1.5 megabytes.

Features

• Clean project architucture
• Separate driver and drawing applications (implement IPC for them and make public API to use in another applications)
• Support more (than one) wired graphics tablets
• Pressure affects line thickness
• Lines can be of 10 colors (Tableau palette is currently hardcoded)
• Surface clearing
• (testing) Export surface to PNG
• Drawing straight lines
• Changing line thickness
• Multiple pages (adding new ones, deleting and navigating through existing ones)
• Batch PNG export (to PDF?)
• Export to vector formats (direct PDF or SVG) (compute shader is required, i.e. OpenGL ES 3.1, i.e. Android 5.0+)
• Line transformation (move, rotate, scale, delete), requires new tricky shaders to get ID of selected lines
• Undo/Redo

Build (*nix)

You don't need an entire Android Studio to build an app. See sdk.mk. You need JDK (currently at least version 16 to use commandline-tools), Android SDK and build-tools. You can download the last two using . In sdk.mk specify the path to the downloaded SDK, platform version and build-tools version. The build also requires a key store.

Then just

make

Install ajournal.apk via adb or just transfer package to your phone and install manually.