zgui v0.2.0 - dear imgui bindings

Easy to use, hand-crafted API with default arguments, named parameters and Zig style text formatting. Here is a simple sample application, and here is a full one.

Features

• Most public dear imgui API exposed
• All memory allocations go through user provided Zig allocator
• DrawList API for vector graphics, text rendering and custom widgets
• Plot API for advanced data visualizations
• Test engine API for automatic testing

Versions

• ImGui 1.90.4-docking
• ImGui test engine 1.90.4
• ImPlot O.17

Getting started

Copy zgui to a subdirectory in your project and add the following to your build.zig.zon .dependencies:

    .zgui = .{ .path = "libs/zgui" },

To get glfw/wgpu rendering backend working also copy zglfw, system-sdk, zgpu and zpool folders and add the depenency paths (see zgpu for the details).

Then in your build.zig add:

pub fn build(b: *std.Build) void {
    const exe = b.addExecutable(.{ ... });

    const zgui = b.dependency("zgui", .{
        .shared = false,
        .with_implot = true,
    });
    exe.root_module.addImport("zgui", zgui.module("root"));
    exe.linkLibrary(zgui.artifact("imgui"));
    
    { // Needed for glfw/wgpu rendering backend
        const zglfw = b.dependency("zglfw", .{});
        exe.root_module.addImport("zglfw", zglfw.module("root"));
        exe.linkLibrary(zglfw.artifact("glfw"));

        const zpool = b.dependency("zpool", .{});
        exe.root_module.addImport("zpool", zpool.module("root"));

        const zgpu = b.dependency("zgpu", .{});
        exe.root_module.addImport("zgpu", zgpu.module("root"));
        exe.linkLibrary(zgpu.artifact("zdawn"));
    }
}

Now in your code you may import and use zgui:

const zgui = @import("zgui");

zgui.init(allocator);

_ = zgui.io.addFontFromFile(content_dir ++ "Roboto-Medium.ttf", 16.0);

zgui.backend.init(
    window,
    demo.gctx.device,
    @enumToInt(swapchain_format),
    @enumToInt(depth_format),
);

// Main loop
while (...) {
    zgui.backend.newFrame(framebuffer_width, framebuffer_height);

    zgui.bulletText(
        "Average :  {d:.3} ms/frame ({d:.1} fps)",
        .{ demo.gctx.stats.average_cpu_time, demo.gctx.stats.fps },
    );
    zgui.bulletText("W, A, S, D :  move camera", .{});
    zgui.spacing();

    if (zgui.button("Setup Scene", .{})) {
        // Button pressed.
    }

    if (zgui.dragFloat("Drag 1", .{ .v = &value0 })) {
        // value0 has changed
    }

    if (zgui.dragFloat("Drag 2", .{ .v = &value0, .min = -1.0, .max = 1.0 })) {
        // value1 has changed
    }

    // Setup wgpu render pass here

    zgui.backend.draw(pass);
}

Building a shared library

If your project spans multiple zig modules that both use ImGui, such as an exe paired with a dll, you may want to build the zgui dependencies (zgui_pkg.zgui_c_cpp) as a shared library. This can be enabled with the shared build option. Then, in build.zig, use zgui_pkg.link to link zgui to all the modules that use ImGui.

When built this way, the ImGui context will be located in the shared library. However, the zgui zig code (which is compiled separately into each module) requires its own memory buffer which has to be initialized separately with initNoContext.

In your executable:

const zgui = @import("zgui");
zgui.init(allocator);
defer zgui.deinit();

In your shared library:

const zgui = @import("zgui");
zgui.initNoContext(allocator);
defer zgui.deinitNoContxt();

DrawList API

draw_list.addQuad(.{
    .p1 = .{ 170, 420 },
    .p2 = .{ 270, 420 },
    .p3 = .{ 220, 520 },
    .p4 = .{ 120, 520 },
    .col = 0xff_00_00_ff,
    .thickness = 3.0,
});
draw_list.addText(.{ 130, 130 }, 0xff_00_00_ff, "The number is: {}", .{7});
draw_list.addCircleFilled(.{ .p = .{ 200, 600 }, .r = 50, .col = 0xff_ff_ff_ff });
draw_list.addCircle(.{ .p = .{ 200, 600 }, .r = 30, .col = 0xff_00_00_ff, .thickness = 11 });
draw_list.addPolyline(
    &.{ .{ 100, 700 }, .{ 200, 600 }, .{ 300, 700 }, .{ 400, 600 } },
    .{ .col = 0xff_00_aa_11, .thickness = 7 },
);

Plot API

if (zgui.plot.beginPlot("Line Plot", .{ .h = -1.0 })) {
    zgui.plot.setupAxis(.x1, .{ .label = "xaxis" });
    zgui.plot.setupAxisLimits(.x1, .{ .min = 0, .max = 5 });
    zgui.plot.setupLegend(.{ .south = true, .west = true }, .{});
    zgui.plot.setupFinish();
    zgui.plot.plotLineValues("y data", i32, .{ .v = &.{ 0, 1, 0, 1, 0, 1 } });
    zgui.plot.plotLine("xy data", f32, .{
        .xv = &.{ 0.1, 0.2, 0.5, 2.5 },
        .yv = &.{ 0.1, 0.3, 0.5, 0.9 },
    });
    zgui.plot.endPlot();
}

Test Engine API

Zig wraper for ImGUI test engine.

var check_b = false;
var _te: *zgui.te.TestEngine = zgui.te.getTestEngine().?;
fn registerTests() void {
    _ = _te.registerTest(
        "Awesome",
        "should_do_some_another_magic",
        @src(),
        struct {
            pub fn gui(ctx: *zgui.te.TestContext) !void {
                _ = ctx; // autofix
                _ = zgui.begin("Test Window", .{ .flags = .{ .no_saved_settings = true } });
                defer zgui.end();

                zgui.text("Hello, automation world", .{});
                _ = zgui.button("Click Me", .{});
                if (zgui.treeNode("Node")) {
                    defer zgui.treePop();

                    _ = zgui.checkbox("Checkbox", .{ .v = &check_b });
                }
            }

            pub fn run(ctx: *zgui.te.TestContext) !void {
                ctx.setRef("/Test Window");
                ctx.windowFocus("");

                ctx.itemAction(.click, "Click Me", .{}, null);
                ctx.itemAction(.open, "Node", .{}, null);
                ctx.itemAction(.check, "Node/Checkbox", .{}, null);
                ctx.itemAction(.uncheck, "Node/Checkbox", .{}, null);

                std.testing.expect(true) catch |err| {
                    zgui.te.checkTestError(@src(), err);
                    return;
                };
            }
        },
    );
}