macos: rendering basic imgui

include/ghostty.h

@@ -27,6 +27,7 @@ extern "C" {
 typedef void *ghostty_app_t;
 typedef void *ghostty_config_t;
 typedef void *ghostty_surface_t;
+typedef void *ghostty_inspector_t;
 
 // Enums are up top so we can reference them later.
 typedef enum {
@@ -399,6 +400,14 @@ void ghostty_surface_split_focus(ghostty_surface_t, ghostty_split_focus_directio
 bool ghostty_surface_binding_action(ghostty_surface_t, const char *, uintptr_t);
 void ghostty_surface_complete_clipboard_request(ghostty_surface_t, const char *, uintptr_t, void *);
 
+ghostty_inspector_t ghostty_surface_inspector(ghostty_surface_t);
+void ghostty_inspector_free(ghostty_surface_t);
+bool ghostty_inspector_metal_init(ghostty_inspector_t, void *);
+void ghostty_inspector_metal_render(ghostty_inspector_t, void *, void *);
+bool ghostty_inspector_metal_shutdown(ghostty_inspector_t);
+void ghostty_inspector_set_content_scale(ghostty_inspector_t, double, double);
+void ghostty_inspector_set_size(ghostty_inspector_t, uint32_t, uint32_t);
+
 // APIs I'd like to get rid of eventually but are still needed for now.
 // Don't use these unless you know what you're doing.
 void ghostty_set_window_background_blur(ghostty_surface_t, void *);

macos/Sources/Ghostty/InspectorView.swift

@@ -1,6 +1,7 @@
 import Foundation
 import MetalKit
 import SwiftUI
+import GhosttyKit
 
 extension Ghostty {
     /// InspectableSurface is a type of Surface view that allows an inspector to be attached.
@@ -13,20 +14,38 @@ extension Ghostty {
             SplitView(.vertical, left: {
                 SurfaceWrapper(surfaceView: surfaceView, isSplit: isSplit)
             }, right: {
-                SurfaceInspector()
+                InspectorViewRepresentable(surfaceView: surfaceView)
             })
         }
     }
     
-    struct SurfaceInspector: View {
-        var body: some View {
-            MetalView<InspectorView>()
+    struct InspectorViewRepresentable: NSViewRepresentable {
+        /// The surface that this inspector represents.
+        let surfaceView: SurfaceView
+
+        func makeNSView(context: Context) -> InspectorView {
+            let view = InspectorView()
+            view.surfaceView = self.surfaceView
+            return view
+        }
+
+        func updateNSView(_ view: InspectorView, context: Context) {
+            view.surfaceView = self.surfaceView
         }
     }
     
     class InspectorView: MTKView {
         let commandQueue: MTLCommandQueue
         
+        var surfaceView: SurfaceView? = nil {
+            didSet { surfaceViewDidChange() }
+        }
+        
+        private var inspector: ghostty_inspector_t? {
+            guard let surfaceView = self.surfaceView else { return nil }
+            return surfaceView.inspector
+        }
+        
         override init(frame: CGRect, device: MTLDevice?) {
             // Initialize our Metal primitives
             guard
@@ -41,7 +60,7 @@ extension Ghostty {
             
             // After initializing the parent we can set our own properties
             self.device = MTLCreateSystemDefaultDevice()
-            self.clearColor = MTLClearColor(red: 1.0, green: 0.0, blue: 0.0, alpha: 1.0)
+            self.clearColor = MTLClearColor(red: 0x28 / 0xFF, green: 0x2C / 0xFF, blue: 0x34 / 0xFF, alpha: 1.0)
             
             // Setup our tracking areas for mouse events
             updateTrackingAreas()
@@ -55,6 +74,30 @@ extension Ghostty {
             trackingAreas.forEach { removeTrackingArea($0) }
         }
         
+        // MARK: Internal Inspector Funcs
+        
+        private func surfaceViewDidChange() {
+            guard let inspector = self.inspector else { return }
+            guard let device = self.device else { return }
+            let devicePtr = Unmanaged.passRetained(device).toOpaque()
+            ghostty_inspector_metal_init(inspector, devicePtr)
+        }
+        
+        private func updateSize() {
+            guard let inspector = self.inspector else { return }
+
+            // Detect our X/Y scale factor so we can update our surface
+            let fbFrame = self.convertToBacking(self.frame)
+            let xScale = fbFrame.size.width / self.frame.size.width
+            let yScale = fbFrame.size.height / self.frame.size.height
+            ghostty_inspector_set_content_scale(inspector, xScale, yScale)
+
+            // When our scale factor changes, so does our fb size so we send that too
+            ghostty_inspector_set_size(inspector, UInt32(fbFrame.size.width), UInt32(fbFrame.size.height))
+        }
+        
+        // MARK: NSView
+        
         override func updateTrackingAreas() {
             // To update our tracking area we just recreate it all.
             trackingAreas.forEach { removeTrackingArea($0) }
@@ -76,17 +119,31 @@ extension Ghostty {
                 userInfo: nil))
         }
         
+        override func viewDidChangeBackingProperties() {
+            super.viewDidChangeBackingProperties()
+            updateSize()
+        }
+        
+        override func resize(withOldSuperviewSize oldSize: NSSize) {
+            super.resize(withOldSuperviewSize: oldSize)
+            updateSize()
+        }
+        
+        // MARK: MTKView
+        
         override func draw(_ dirtyRect: NSRect) {
             guard
               let commandBuffer = self.commandQueue.makeCommandBuffer(),
-              let descriptor = self.currentRenderPassDescriptor,
-              let renderEncoder =
-                commandBuffer.makeRenderCommandEncoder(
-                  descriptor: descriptor) else {
+              let descriptor = self.currentRenderPassDescriptor else {
                 return
             }
+            
+            ghostty_inspector_metal_render(
+                inspector,
+                Unmanaged.passRetained(commandBuffer).toOpaque(),
+                Unmanaged.passRetained(descriptor).toOpaque()
+            )
 
-            renderEncoder.endEncoding()
             guard let drawable = self.currentDrawable else { return }
             commandBuffer.present(drawable)
             commandBuffer.commit()

macos/Sources/Ghostty/SurfaceView.swift

@@ -233,7 +233,7 @@ extension Ghostty {
             return config
         }
     }
-
+    
     /// The NSView implementation for a terminal surface.
     class SurfaceView: NSView, NSTextInputClient, ObservableObject {
         // The current title of the surface as defined by the pty. This can be
@@ -245,6 +245,13 @@ extension Ghostty {
         // then the view is moved to a new window.
         var initialSize: NSSize? = nil
         
+        // Returns the inspector instance for this surface, or nil if the
+        // surface has been closed.
+        var inspector: ghostty_inspector_t? {
+            guard let surface = self.surface else { return nil }
+            return ghostty_surface_inspector(surface)
+        }
+        
         private(set) var surface: ghostty_surface_t?
         var error: Error? = nil
 

src/apprt/embedded.zig

@@ -195,6 +195,7 @@ pub const Surface = struct {
     cursor_pos: apprt.CursorPos,
     opts: Options,
     keymap_state: input.Keymap.State,
+    inspector: ?*Inspector = null,
 
     pub const Options = extern struct {
         /// Userdata passed to some of the callbacks.
@@ -290,6 +291,9 @@ pub const Surface = struct {
     }
 
     pub fn deinit(self: *Surface) void {
+        // Shut down our inspector
+        self.freeInspector();
+
         // Remove ourselves from the list of known surfaces in the app.
         self.app.core_app.deleteSurface(self);
 
@@ -297,6 +301,28 @@ pub const Surface = struct {
         self.core_surface.deinit();
     }
 
+    /// Initialize the inspector instance. A surface can only have one
+    /// inspector at any given time, so this will return the previous inspector
+    /// if it was already initialized.
+    pub fn initInspector(self: *Surface) !*Inspector {
+        if (self.inspector) |v| return v;
+
+        const alloc = self.app.core_app.alloc;
+        var inspector = try alloc.create(Inspector);
+        errdefer alloc.destroy(inspector);
+        inspector.* = try Inspector.init(self);
+        self.inspector = inspector;
+        return inspector;
+    }
+
+    pub fn freeInspector(self: *Surface) void {
+        if (self.inspector) |v| {
+            v.deinit();
+            self.app.core_app.alloc.destroy(v);
+            self.inspector = null;
+        }
+    }
+
     pub fn newSplit(self: *const Surface, direction: input.SplitDirection) !void {
         const func = self.app.opts.new_split orelse {
             log.info("runtime embedder does not support splits", .{});
@@ -781,6 +807,141 @@ pub const Surface = struct {
     }
 };
 
+/// Inspector is the state required for the terminal inspector. A terminal
+/// inspector is 1:1 with a Surface.
+pub const Inspector = struct {
+    const cimgui = @import("cimgui");
+
+    surface: *Surface,
+    ig_ctx: *cimgui.c.ImGuiContext,
+    backend: ?Backend = null,
+
+    /// Our previous instant used to calculate delta time for animations.
+    instant: ?std.time.Instant = null,
+
+    const Backend = enum {
+        metal,
+
+        pub fn deinit(self: Backend) void {
+            switch (self) {
+                .metal => cimgui.c.ImGui_ImplMetal_Shutdown(),
+            }
+        }
+    };
+
+    pub fn init(surface: *Surface) !Inspector {
+        const ig_ctx = cimgui.c.igCreateContext(null);
+        errdefer cimgui.c.igDestroyContext(ig_ctx);
+        cimgui.c.igSetCurrentContext(ig_ctx);
+        const io: *cimgui.c.ImGuiIO = cimgui.c.igGetIO();
+        io.BackendPlatformName = "ghostty_embedded";
+
+        return .{
+            .surface = surface,
+            .ig_ctx = ig_ctx,
+        };
+    }
+
+    pub fn deinit(self: *Inspector) void {
+        cimgui.c.igSetCurrentContext(self.ig_ctx);
+        if (self.backend) |v| v.deinit();
+        cimgui.c.igDestroyContext(self.ig_ctx);
+    }
+
+    /// Initialize the inspector for a metal backend.
+    pub fn initMetal(self: *Inspector, device: objc.Object) bool {
+        defer device.msgSend(void, objc.sel("release"), .{});
+        cimgui.c.igSetCurrentContext(self.ig_ctx);
+
+        if (self.backend) |v| {
+            v.deinit();
+            self.backend = null;
+        }
+
+        if (!cimgui.c.ImGui_ImplMetal_Init(device.value)) {
+            log.warn("failed to initialize metal backend", .{});
+            return false;
+        }
+        self.backend = .metal;
+
+        log.debug("initialized metal backend", .{});
+        return true;
+    }
+
+    pub fn renderMetal(
+        self: *Inspector,
+        command_buffer: objc.Object,
+        desc: objc.Object,
+    ) !void {
+        defer {
+            command_buffer.msgSend(void, objc.sel("release"), .{});
+            desc.msgSend(void, objc.sel("release"), .{});
+        }
+        assert(self.backend == .metal);
+        //log.debug("render", .{});
+
+        // Setup our imgui frame
+        {
+            cimgui.c.ImGui_ImplMetal_NewFrame(desc.value);
+            try self.newFrame();
+            cimgui.c.igNewFrame();
+
+            // Build our UI
+            var show: bool = true;
+            cimgui.c.igShowDemoWindow(&show);
+
+            // Render
+            cimgui.c.igRender();
+        }
+
+        // MTLRenderCommandEncoder
+        const encoder = command_buffer.msgSend(
+            objc.Object,
+            objc.sel("renderCommandEncoderWithDescriptor:"),
+            .{desc.value},
+        );
+        defer encoder.msgSend(void, objc.sel("endEncoding"), .{});
+        cimgui.c.ImGui_ImplMetal_RenderDrawData(
+            cimgui.c.igGetDrawData(),
+            command_buffer.value,
+            encoder.value,
+        );
+    }
+
+    pub fn updateContentScale(self: *Inspector, x: f64, y: f64) void {
+        cimgui.c.igSetCurrentContext(self.ig_ctx);
+        const io: *cimgui.c.ImGuiIO = cimgui.c.igGetIO();
+        io.DisplayFramebufferScale = .{
+            .x = @floatCast(x),
+            .y = @floatCast(y),
+        };
+    }
+
+    pub fn updateSize(self: *Inspector, width: u32, height: u32) void {
+        cimgui.c.igSetCurrentContext(self.ig_ctx);
+        const io: *cimgui.c.ImGuiIO = cimgui.c.igGetIO();
+        const x_scale: u32 = @intFromFloat(io.DisplayFramebufferScale.x);
+        const y_scale: u32 = @intFromFloat(io.DisplayFramebufferScale.y);
+        io.DisplaySize = .{
+            .x = @floatFromInt(@divFloor(width, x_scale)),
+            .y = @floatFromInt(@divFloor(height, y_scale)),
+        };
+    }
+
+    fn newFrame(self: *Inspector) !void {
+        const io: *cimgui.c.ImGuiIO = cimgui.c.igGetIO();
+
+        // Determine our delta time
+        const now = try std.time.Instant.now();
+        io.DeltaTime = if (self.instant) |prev| delta: {
+            const since_ns = now.since(prev);
+            const since_s: f32 = @floatFromInt(since_ns / std.time.ns_per_s);
+            break :delta @max(0.00001, since_s);
+        } else (1 / 60);
+        self.instant = now;
+    }
+};
+
 // C API
 pub const CAPI = struct {
     const global = &@import("../main.zig").state;
@@ -1047,6 +1208,50 @@ pub const CAPI = struct {
         };
     }
 
+    export fn ghostty_surface_inspector(ptr: *Surface) ?*Inspector {
+        return ptr.initInspector() catch |err| {
+            log.err("error initializing inspector err={}", .{err});
+            return null;
+        };
+    }
+
+    export fn ghostty_inspector_free(ptr: *Surface) void {
+        ptr.freeInspector();
+    }
+
+    export fn ghostty_inspector_metal_init(ptr: *Inspector, device: objc.c.id) bool {
+        return ptr.initMetal(objc.Object.fromId(device));
+    }
+
+    export fn ghostty_inspector_metal_render(
+        ptr: *Inspector,
+        command_buffer: objc.c.id,
+        descriptor: objc.c.id,
+    ) void {
+        return ptr.renderMetal(
+            objc.Object.fromId(command_buffer),
+            objc.Object.fromId(descriptor),
+        ) catch |err| {
+            log.err("error rendering inspector err={}", .{err});
+            return;
+        };
+    }
+
+    export fn ghostty_inspector_metal_shutdown(ptr: *Inspector) void {
+        if (ptr.backend) |v| {
+            v.deinit();
+            ptr.backend = null;
+        }
+    }
+
+    export fn ghostty_inspector_set_size(ptr: *Inspector, w: u32, h: u32) void {
+        ptr.updateSize(w, h);
+    }
+
+    export fn ghostty_inspector_set_content_scale(ptr: *Inspector, x: f64, y: f64) void {
+        ptr.updateContentScale(x, y);
+    }
+
     /// Sets the window background blur on macOS to the desired value.
     /// I do this in Zig as an extern function because I don't know how to
     /// call these functions in Swift.