lvgl.zig

//! LVGL Module that wraps the LVGL API (incomplete)

/// Import the Zig Standard Library
const std = @import("std");

/// Import the LVGL Library from C
const c = @cImport({
    // NuttX Defines
    @cDefine("__NuttX__",  "");
    @cDefine("NDEBUG",     "");
    @cDefine("ARCH_RISCV", "");
    @cDefine("LV_LVGL_H_INCLUDE_SIMPLE", "");

    // Workaround for "Unable to translate macro: undefined identifier `LL`"
    @cDefine("LL", "");
    @cDefine("__int_c_join(a, b)", "a");  //  Bypass zig/lib/include/stdint.h

    // NuttX Header Files
    @cInclude("arch/types.h");
    @cInclude("../../nuttx/include/limits.h");

    // LVGL Header Files
    @cInclude("lvgl/lvgl.h");
});

/// Return the Active Screen
pub fn getActiveScreen() !Object {

    // Get the Active Screen
    const screen = c.lv_scr_act();

    // If successfully fetched...
    if (screen) |s| {
        // Wrap Active Screen as Object and return it
        return Object.init(s);
    } else {
        // Unable to get Active Screen
        std.log.err("lv_scr_act failed", .{});
        return LvglError.UnknownError;
    }
}

/// LVGL Object
pub const Object = struct {

    /// Pointer to LVGL Object
    obj: *c.lv_obj_t,

    /// Init the Object
    pub fn init(obj: *c.lv_obj_t) Object {
        return .{ .obj = obj };
    }

    /// Create a Label as a child of the Object
    pub fn createLabel(self: *Object) !Label {

        // Assume we won't copy from another Object 
        const copy: ?*const c.lv_obj_t = null;

        // Create the Label
        const label = c.lv_label_create(self.obj, copy);

        // If successfully created...
        if (label) |l| {
            // Wrap as Label and return it
            return Label.init(l);
        } else {
            // Unable to create Label
            std.log.err("lv_label_create failed", .{});
            return LvglError.UnknownError;
        }
    }
};

/// LVGL Label
pub const Label = struct {

    /// Pointer to LVGL Label
    obj: *c.lv_obj_t,

    /// Init the Label
    pub fn init(obj: *c.lv_obj_t) Label {
        return .{ .obj = obj };
    }

    /// Set the wrapping of long lines in the label text
    pub fn setLongMode(self: *Label, long_mode: c.lv_label_long_mode_t) void {
        c.lv_label_set_long_mode(self.obj, long_mode);
    }

    /// Set the label text alignment
    pub fn setAlign(self: *Label, alignment: c.lv_label_align_t) void {
        c.lv_label_set_align(self.obj, alignment);
    }

    /// Enable or disable color codes in the label text
    pub fn setRecolor(self: *Label, en: bool) void {
        c.lv_label_set_recolor(self.obj, en);
    }

    /// Set the label text and colors
    pub fn setText(self: *Label, text: [*c]const u8) void {
        c.lv_label_set_text(self.obj, text);
    }

    /// Set the object width
    pub fn setWidth(self: *Label, w: c.lv_coord_t) void {
        c.lv_obj_set_width(self.obj, w);
    }

    /// Set the object alignment
    pub fn alignObject(self: *Label, alignment: c.lv_align_t, x_ofs: c.lv_coord_t, y_ofs: c.lv_coord_t) void {
        const base: ?*const c.lv_obj_t = null;
        c.lv_obj_align(self.obj, base, alignment, x_ofs, y_ofs);
    }
};

/// LVGL Errors
pub const LvglError = error{ UnknownError };