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diff --git a/doc/ExternalResources.md b/doc/ExternalResources.md new file mode 100644 index 00000000..85319f6f --- /dev/null +++ b/doc/ExternalResources.md @@ -0,0 +1,70 @@ +# External resources +Since InfiniTime 1.11 apps and watchfaces can benefit from the external flash memory to store images and fonts. +This external memory is a lot bigger (4MB) than the internal memory that contains the firmware (512KB). + +This page describes how the resources are integrated in InfiniTime from a developer perspective. [This page](gettingStarted/updating-software.md) explains how to install and update the external resources using companion apps. + +## Resources generation + +Resources are generated at build time via the [CMake target `Generate Resources`](https://github.com/InfiniTimeOrg/InfiniTime/blob/develop/src/resources/CMakeLists.txt#L19). +It runs 3 Python scripts that respectively convert the fonts to binary format, convert the images to binary format and package everything in a .zip file. + +The resulting file `infinitime-resources-x.y.z.zip` contains the images and fonts converted in binary `.bin` files and a JSON file `resources.json`. + +Companion apps use this file to upload the files to the watch. + +``` +{ + "resources": [ + { + "filename": "lv_font_dots_40.bin", + "path": "/fonts/lv_font_dots_40.bin" + } + ], + "obsolete_files": [ + { + "path": "/example-of-obsolete-file.bin", + "since": "1.11.0" + } + ] +} +``` + +The resource JSON file describes an array of resources and an array of obsolete files : + +- `resources` : a resource is a file that must be flashed to the watch + - `filename`: name of the resources in the zip file. + - `path` : file path and name where the file must be flashed in the watch FS. + +- `obsolete_files` : files that are not needed anymore in the memory of the watch that can be deleted during the update procedure. + - `path` : path of the file in the watch FS + - `since` : version of InfiniTime that made this file obsolete. + +## Resources update procedure + +The update procedure is based on the [BLE FS API](BLEFS.md). The companion app simply write the binary files to the watch FS using information from the file `resources.json`. + +## Working with external resources in the code + +Load a picture from the external resources: + +``` +lv_obj_t* logo = lv_img_create(lv_scr_act(), nullptr); +lv_img_set_src(logo, "F:/images/logo.bin"); +``` + +Load a font from the external resources: you first need to check that the file actually exists. LVGL will crash when trying to open a font that doesn't exist. + +``` +lv_font_t* font_teko = nullptr; +if (filesystem.FileOpen(&f, "/fonts/font.bin", LFS_O_RDONLY) >= 0) { + filesystem.FileClose(&f); + font_teko = lv_font_load("F:/fonts/font.bin"); +} + +if(font != nullptr) { + lv_obj_set_style_local_text_font(label, LV_LABEL_PART_MAIN, LV_STATE_DEFAULT, font); +} + +``` + |