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Diffstat (limited to 'doc/develop')
| -rw-r--r-- | doc/develop/expo.rst | 305 |
1 files changed, 294 insertions, 11 deletions
diff --git a/doc/develop/expo.rst b/doc/develop/expo.rst index 32dd7f09030..2ac4af232da 100644 --- a/doc/develop/expo.rst +++ b/doc/develop/expo.rst @@ -85,6 +85,9 @@ or even the IDs of objects. Programmatic creation of many items in a loop can be handled by allocating space in the enum for a maximum number of items, then adding the loop count to the enum values to obtain unique IDs. +Where dynamic IDs are need, use expo_set_dynamic_start() to set the start value, +so that they are allocated above the starting (enum) IDs. + All text strings are stored in a structure attached to the expo, referenced by a text ID. This makes it easier at some point to implement multiple languages or to support Unicode strings. @@ -97,10 +100,13 @@ objects first, then create the menu item, passing in the relevant IDs. Creating an expo ---------------- -To create an expo, use `expo_new()` followed by `scene_new()` to create a scene. -Then add objects to the scene, using functions like `scene_txt_str()` and -`scene_menu()`. For every menu item, add text and image objects, then create -the menu item with `scene_menuitem()`, referring to those objects. +To create an expo programmatically, use `expo_new()` followed by `scene_new()` +to create a scene. Then add objects to the scene, using functions like +`scene_txt_str()` and `scene_menu()`. For every menu item, add text and image +objects, then create the menu item with `scene_menuitem()`, referring to those +objects. + +To create an expo using a description file, see :ref:`expo_format` below. Layout ------ @@ -152,8 +158,287 @@ such as scanning devices for more bootflows. Themes ------ -Expo does not itself support themes. The bootflow_menu implement supposed a -basic theme, applying font sizes to the various text objects in the expo. +Expo supports simple themes, for setting the font size, for example. Use the +expo_apply_theme() function to load a theme, passing a node with the required +properties: + +font-size + Font size to use for all text (type: u32) + +menu-inset + Number of pixels to inset the menu on the sides and top (type: u32) + +menuitem-gap-y + Number of pixels between menu items + +Pop-up mode +----------- + +Expos support two modes. The simple mode is used for selecting from a single +menu, e.g. when choosing with OS to boot. In this mode the menu items are shown +in a list (label, > pointer, key and description) and can be chosen using arrow +keys and enter:: + + U-Boot Boot Menu + + UP and DOWN to choose, ENTER to select + + mmc1 > 0 Fedora-Workstation-armhfp-31-1.9 + mmc3 1 Armbian + +The popup mode allows multiple menus to be present in a scene. Each is shown +just as its title and label, as with the `CPU Speed` and `AC Power` menus here:: + + Test Configuration + + + CPU Speed <2 GHz> (highlighted) + + AC Power Always Off + + + UP and DOWN to choose, ENTER to select + + +.. _expo_format: + +Expo Format +----------- + +It can be tedious to create a complex expo using code. Expo supports a +data-driven approach, where the expo description is in a devicetree file. This +makes it easier and faster to create and edit the description. An expo builder +is provided to convert this format into an expo structure. + +Layout of the expo scenes is handled automatically, based on a set of simple +rules. The :doc:`../usage/cmd/cedit` can be used to load a configuration +and create an expo from it. + +Top-level node +~~~~~~~~~~~~~~ + +The top-level node has the following properties: + +dynamic-start + type: u32, optional + + Specifies the start of the dynamically allocated objects. This results in + a call to expo_set_dynamic_start(). + +The top-level node has the following subnodes: + +scenes + Specifies the scenes in the expo, each one being a subnode + +strings + Specifies the strings in the expo, each one being a subnode + +`scenes` node +~~~~~~~~~~~~~ + +Contains a list of scene subnodes. The name of each subnode is passed as the +name to `scene_new()`. + +`strings` node +~~~~~~~~~~~~~~ + +Contains a list of string subnodes. The name of each subnode is ignored. + +`strings` subnodes +~~~~~~~~~~~~~~~~~~ + +Each subnode defines a string which can be used by scenes and objects. Each +string has an ID number which is used to refer to it. + +The `strings` subnodes have the following properties: + +id + type: u32, required + + Specifies the ID number for the string. + +value: + type: string, required + + Specifies the string text. For now only a single value is supported. Future + work may add support for multiple languages by using a value for each + language. + +Scene nodes (`scenes` subnodes) +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Each subnode of the `scenes` node contains a scene description. + +Most properties can use either a string or a string ID. For example, a `title` +property can be used to provide the title for a menu; alternatively a `title-id` +property can provide the string ID of the title. If both are present, the +ID takes preference, except that if a string with that ID does not exist, it +falls back to using the string from the property (`title` in this example). The +description below shows these are alternative properties with the same +description. + +The scene nodes have the following properties: + +id + type: u32, required + + Specifies the ID number for the string. + +title / title-id + type: string / u32, required + + Specifies the title of the scene. This is shown at the top of the scene. + +prompt / prompt-id + type: string / u32, required + + Specifies a prompt for the scene. This is shown at the bottom of the scene. + +The scene nodes have a subnode for each object in the scene. + +Object nodes +~~~~~~~~~~~~ + +The object-node name is used as the name of the object, e.g. when calling +`scene_menu()` to create a menu. + +Object nodes have the following common properties: + +type + type: string, required + + Specifies the type of the object. Valid types are: + + "menu" + Menu containing items which can be selected by the user + +id + type: u32, required + + Specifies the ID of the object. This is used when referring to the object. + + +Menu nodes have the following additional properties: + +title / title-id + type: string / u32, required + + Specifies the title of the menu. This is shown to the left of the area for + this menu. + +item-id + type: u32 list, required + + Specifies the ID for each menu item. These are used for checking which item + has been selected. + +item-label / item-label-id + type: string list / u32 list, required + + Specifies the label for each item in the menu. These are shown to the user. + In 'popup' mode these form the items in the menu. + +key-label / key-label-id + type: string list / u32 list, optional + + Specifies the key for each item in the menu. These are currently only + intended for use in simple mode. + +desc-label / desc-label-id + type: string list / u32 list, optional + + Specifies the description for each item in the menu. These are currently + only intended for use in simple mode. + + +Expo layout +~~~~~~~~~~~ + +The `expo_arrange()` function can be called to arrange the expo objects in a +suitable manner. For each scene it puts the title at the top, the prompt at the +bottom and the objects in order from top to bottom. + +Expo format example +~~~~~~~~~~~~~~~~~~~ + +This example shows an expo with a single scene consisting of two menus. The +scene title is specified using a string from the strings table, but all other +strings are provided inline in the nodes where they are used. + +:: + + #define ID_PROMPT 1 + #define ID_SCENE1 2 + #define ID_SCENE1_TITLE 3 + + #define ID_CPU_SPEED 4 + #define ID_CPU_SPEED_TITLE 5 + #define ID_CPU_SPEED_1 6 + #define ID_CPU_SPEED_2 7 + #define ID_CPU_SPEED_3 8 + + #define ID_POWER_LOSS 9 + #define ID_AC_OFF 10 + #define ID_AC_ON 11 + #define ID_AC_MEMORY 12 + + #define ID_DYNAMIC_START 13 + + &cedit { + dynamic-start = <ID_DYNAMIC_START>; + + scenes { + main { + id = <ID_SCENE1>; + + /* value refers to the matching id in /strings */ + title-id = <ID_SCENE1_TITLE>; + + /* simple string is used as it is */ + prompt = "UP and DOWN to choose, ENTER to select"; + + /* defines a menu within the scene */ + cpu-speed { + type = "menu"; + id = <ID_CPU_SPEED>; + + /* + * has both string and ID. The string is ignored + * if the ID is present and points to a string + */ + title = "CPU speed"; + title-id = <ID_CPU_SPEED_TITLE>; + + /* menu items as simple strings */ + item-label = "2 GHz", "2.5 GHz", "3 GHz"; + + /* IDs for the menu items */ + item-id = <ID_CPU_SPEED_1 ID_CPU_SPEED_2 + ID_CPU_SPEED_3>; + }; + + power-loss { + type = "menu"; + id = <ID_POWER_LOSS>; + + title = "AC Power"; + item-label = "Always Off", "Always On", + "Memory"; + + item-id = <ID_AC_OFF ID_AC_ON ID_AC_MEMORY>; + }; + }; + }; + + strings { + title { + id = <ID_SCENE1_TITLE>; + value = "Test Configuration"; + value-es = "configuración de prueba"; + }; + }; + }; + API documentation ----------------- @@ -166,12 +451,10 @@ Future ideas Some ideas for future work: - Default menu item and a timeout -- Higher-level / automatic / more flexible layout of objects - Image formats other than BMP - Use of ANSI sequences to control a serial terminal - Colour selection -- Better support for handling lots of settings, e.g. with multiple menus and - radio/option widgets +- Support for more widgets, e.g. text, numeric, radio/option - Mouse support - Integrate Nuklear, NxWidgets or some other library for a richer UI - Optimise rendering by only updating the display with changes since last render @@ -179,10 +462,10 @@ Some ideas for future work: - Add a Kconfig option to drop the names to save code / data space - Add a Kconfig option to disable vidconsole support to save code / data space - Support both graphical and text menus at the same time on different devices -- Implement proper measurement of object bounding boxes, to permit more exact - layout. This would tidy up the layout when Truetype is not used - Support unicode - Support curses for proper serial-terminal menus +- Add support for large menus which need to scroll +- Add support for reading and writing configuration settings with cedit .. Simon Glass <sjg@chromium.org> .. 7-Oct-22 |