Fix up API calls for initialization

pkg/dcimgui/build.zig

@@ -133,6 +133,11 @@ pub fn build(b: *std.Build) !void {
             },
             .flags = flags.items,
         });
+        lib.addCSourceFiles(.{
+            .root = b.path(""),
+            .files = &.{"ext.cpp"},
+            .flags = flags.items,
+        });
 
         lib.installHeadersDirectory(
             upstream.path(""),

pkg/dcimgui/ext.cpp

@@ -0,0 +1,30 @@
+#include "imgui.h"
+
+// This file contains custom extensions for functionality that isn't
+// properly supported by Dear Bindings yet. Namely:
+// https://github.com/dearimgui/dear_bindings/issues/55
+
+// Wrap this in a namespace to keep it separate from the C++ API
+namespace cimgui
+{
+#include "dcimgui.h"
+}
+
+extern "C"
+{
+CIMGUI_API void ImFontConfig_ImFontConfig(cimgui::ImFontConfig* self)
+{
+    static_assert(sizeof(cimgui::ImFontConfig) == sizeof(::ImFontConfig), "ImFontConfig size mismatch");
+    static_assert(alignof(cimgui::ImFontConfig) == alignof(::ImFontConfig), "ImFontConfig alignment mismatch");
+    ::ImFontConfig defaults;
+    *reinterpret_cast<::ImFontConfig*>(self) = defaults;
+}
+
+CIMGUI_API void ImGuiStyle_ImGuiStyle(cimgui::ImGuiStyle* self)
+{
+    static_assert(sizeof(cimgui::ImGuiStyle) == sizeof(::ImGuiStyle), "ImGuiStyle size mismatch");
+    static_assert(alignof(cimgui::ImGuiStyle) == alignof(::ImGuiStyle), "ImGuiStyle alignment mismatch");
+    ::ImGuiStyle defaults;
+    *reinterpret_cast<::ImGuiStyle*>(self) = defaults;
+}
+}

pkg/dcimgui/main.zig

@@ -28,6 +28,12 @@ pub extern fn ImGui_DockBuilderDockWindow(window_name: [*:0]const u8, node_id: c
 pub extern fn ImGui_DockBuilderSplitNode(node_id: c.ImGuiID, split_dir: c.ImGuiDir, size_ratio_for_node_at_dir: f32, out_id_at_dir: *c.ImGuiID, out_id_at_opposite_dir: *c.ImGuiID) callconv(.c) c.ImGuiID;
 pub extern fn ImGui_DockBuilderFinish(node_id: c.ImGuiID) callconv(.c) void;
 
+// Extension functions from ext.cpp
+pub const ext = struct {
+    pub extern fn ImFontConfig_ImFontConfig(self: *c.ImFontConfig) callconv(.c) void;
+    pub extern fn ImGuiStyle_ImGuiStyle(self: *c.ImGuiStyle) callconv(.c) void;
+};
+
 test {
     _ = c;
 }

src/apprt/embedded.zig

@@ -1070,8 +1070,11 @@ pub const Inspector = struct {
         // Cache our scale because we use it for cursor position calculations.
         self.content_scale = x;
 
-        // Setup a new style and scale it appropriately.
-        var style: cimgui.c.ImGuiStyle = .{};
+        // Setup a new style and scale it appropriately. We must use the
+        // ImGuiStyle constructor to get proper default values (e.g.,
+        // CurveTessellationTol) rather than zero-initialized values.
+        var style: cimgui.c.ImGuiStyle = undefined;
+        cimgui.ext.ImGuiStyle_ImGuiStyle(&style);
         cimgui.c.ImGuiStyle_ScaleAllSizes(&style, @floatCast(x));
         const active_style = cimgui.c.ImGui_GetStyle();
         active_style.* = style;

src/apprt/gtk/class/imgui_widget.zig

@@ -255,8 +255,11 @@ pub const ImguiWidget = extern struct {
         io.DisplaySize = .{ .x = @floatFromInt(width), .y = @floatFromInt(height) };
         io.DisplayFramebufferScale = .{ .x = 1, .y = 1 };
 
-        // Setup a new style and scale it appropriately.
-        var style: cimgui.c.ImGuiStyle = .{};
+        // Setup a new style and scale it appropriately. We must use the
+        // ImGuiStyle constructor to get proper default values (e.g.,
+        // CurveTessellationTol) rather than zero-initialized values.
+        var style: cimgui.c.ImGuiStyle = undefined;
+        cimgui.ext.ImGuiStyle_ImGuiStyle(&style);
         cimgui.c.ImGuiStyle_ScaleAllSizes(&style, @floatFromInt(scale_factor));
         const active_style = cimgui.c.ImGui_GetStyle();
         active_style.* = style;

src/inspector/Inspector.zig

@@ -138,23 +138,24 @@ pub fn setup() void {
     io.IniFilename = null;
     io.LogFilename = null;
 
-    // Use our own embedded font
-    {
-        // TODO: This will have to be recalculated for different screen DPIs.
-        // This is currently hardcoded to a 2x content scale.
-        const font_size = 16 * 2;
-
-        var font_config: cimgui.c.ImFontConfig = .{};
-        font_config.FontDataOwnedByAtlas = false;
-        _ = cimgui.c.ImFontAtlas_AddFontFromMemoryTTF(
-            io.Fonts,
-            @ptrCast(@constCast(font.embedded.regular)),
-            font.embedded.regular.len,
-            font_size,
-            &font_config,
-            null,
-        );
-    }
+    // // Use our own embedded font
+    // {
+    //     // TODO: This will have to be recalculated for different screen DPIs.
+    //     // This is currently hardcoded to a 2x content scale.
+    //     const font_size = 16 * 2;
+    //
+    //     var font_config: cimgui.c.ImFontConfig = .{};
+    //     cimgui.ext.ImFontConfig_ImFontConfig(&font_config);
+    //     font_config.FontDataOwnedByAtlas = false;
+    //     _ = cimgui.c.ImFontAtlas_AddFontFromMemoryTTF(
+    //         io.Fonts,
+    //         @ptrCast(@constCast(font.embedded.regular.ptr)),
+    //         @intCast(font.embedded.regular.len),
+    //         font_size,
+    //         &font_config,
+    //         null,
+    //     );
+    // }
 }
 
 pub fn init(surface: *Surface) !Inspector {