Ported Imgui-knobs

[Logickin-Lambda]

Thanks for waiting the setup of my new laptop before going back on working my proposal of porting the knob library.

As proposed in the issues, the library can be conditionally compiled by stating .with_knobs with true:

// zgui
const zgui = b.dependency("zgui", .{
    .shared = false,
    .with_knobs = true,
    .backend = .glfw_wgpu,
   });
exe.root_module.addImport("zgui", zgui.module("root"));
exe.linkLibrary(zgui.artifact("imgui"));

Once the knob part is included, simply call zgui.knobs.knob to create a knob:

// Minimal knob function call
_ = zgui.knobs.knob("Minimal", .{
    .v = &v_knob,
    .v_min = 0,
    .v_max = 1.0,
});

For different knob style, resolution per step, arc shape, and color, we can apply with the additional parameter like shown:

// Styled f32 knob
_ = zgui.knobs.knob("f32 Knob", .{
    .v = &v_knob,
    .v_min = 0,
    .v_max = 1.0,
    .size = 200,
    .speed = 0.0005,
    .angle_min = std.math.pi,
    .angle_max = 2 * std.math.pi,
    .variant = .{ .stepped = true },
    .steps = 5,
});

// Styled i32 knob (applied color)
zgui.pushStyleColor4f(.{ .idx = zgui.StyleCol.button_active, .c = .{ 0.6, 0.2, 0.2, 1 } });
zgui.pushStyleColor4f(.{ .idx = zgui.StyleCol.button_hovered, .c = .{ 0.6, 0.4, 0.4, 1 } });
zgui.pushStyleColor4f(.{ .idx = zgui.StyleCol.button, .c = .{ 0.4, 0, 0, 1 } });
_ = zgui.knobs.knobInt("i32 Knob", .{
    .v = &v_knob_int,
    .v_min = -10,
    .v_max = 10,
    .size = 250,
    .variant = zgui.knobs.KnobVariant{ .wiper_dot = true },
    .flags = zgui.knobs.KnobFlags{
        .drag_horizontal = true,
        .no_input = true,
    },
});
zgui.popStyleColor(.{ .count = 3 });

The result based on the function call above (applied with zgui,sameLine() for the alignments):

Knobs.in.demo.mp4

Time for some code review, and let see if there are further requests to follow.