Debug: added DebugTextEncoding() to help diagnose between text encoding issues and font loading issues. Simplified code + extracted DebugNodeFontGlyph().

Helper to diagnose issues such as #4866, #3558, #3436, #2233, #1880, #1780, #905, #832, #762, #726, #609, #565, #307)

docs/CHANGELOG.txt

@@ -87,6 +87,9 @@ Other Changes:
 - Stack Tool: Added option to copy item path to clipboard. (#4631)
 - Drawlist: Fixed PathArcTo() emitting terminating vertices too close to arc vertices. (#4993) [@thedmd]
 - DrawList: Fixed texture-based anti-aliasing path with RGBA textures (#5132, #3245) [@cfillion]
+- Debug: Added DebugTextEncoding() function to facilitate diagnosing issues when not sure about whether
+  you have a UTF-8 text encoding issue or a font loading issue. [@LaMarche05, @ocornut]
+- Metrics: Added a "UTF-8 Encoding Viewer" section using the aforementioned DebugTextEncoding() function.
 - Misc: Fixed calling GetID("label") _before_ a widget emitting this item inside a group (such as InputInt())
   from causing an assertion when closing the group. (#5181).
 - Misc: Fixed IsAnyItemHovered() returning false when using navigation.

docs/FONTS.md

@@ -29,7 +29,11 @@ In the [misc/fonts/](https://github.com/ocornut/imgui/tree/master/misc/fonts) fo
 
 - You can use the `Metrics/Debugger` window (available in `Demo>Tools`) to browse your fonts and understand what's going on if you have an issue. You can also reach it in `Demo->Tools->Style Editor->Fonts`. The same information are also available in the Style Editor under Fonts.
 
-![imgui_capture_0008](https://user-images.githubusercontent.com/8225057/135429892-0e41ef8d-33c5-4991-bcf6-f997a0bcfd6b.png)
+![Fonts debugging](https://user-images.githubusercontent.com/8225057/135429892-0e41ef8d-33c5-4991-bcf6-f997a0bcfd6b.png)
+
+- You can use the `UTF-8 Encoding viewer` in `Metrics/Debugger` to verify the content of your UTF-8 strings. From C/C++ code, you can call `ImGui::DebugTextEncoding("my string");` function to verify that your UTF-8 encoding is correct.
+
+![UTF-8 Encoding viewer](https://user-images.githubusercontent.com/8225057/166505963-8a0d7899-8ee8-4558-abb2-1ae523dc02f9.png)
 
 - All loaded fonts glyphs are rendered into a single texture atlas ahead of time. Calling either of `io.Fonts->GetTexDataAsAlpha8()`, `io.Fonts->GetTexDataAsRGBA32()` or `io.Fonts->Build()` will build the atlas.
 

imgui.cpp

@@ -12060,11 +12060,15 @@ static void SetPlatformImeDataFn_DefaultImpl(ImGuiViewport*, ImGuiPlatformImeDat
 //-----------------------------------------------------------------------------
 // - RenderViewportThumbnail() [Internal]
 // - RenderViewportsThumbnails() [Internal]
+// - DebugTextEncoding()
 // - MetricsHelpMarker() [Internal]
+// - ShowFontAtlas() [Internal]
 // - ShowMetricsWindow()
 // - DebugNodeColumns() [Internal]
 // - DebugNodeDrawList() [Internal]
 // - DebugNodeDrawCmdShowMeshAndBoundingBox() [Internal]
+// - DebugNodeFont() [Internal]
+// - DebugNodeFontGlyph() [Internal]
 // - DebugNodeStorage() [Internal]
 // - DebugNodeTabBar() [Internal]
 // - DebugNodeViewport() [Internal]
@@ -12127,79 +12131,40 @@ static void RenderViewportsThumbnails()
     ImGui::Dummy(bb_full.GetSize() * SCALE);
 }
 
-static void ShowEncodingViewerChar(ImFont* font, ImWchar c, const char* c_utf8)
+// Helper tool to diagnose between text encoding issues and font loading issues. Pass your UTF-8 string and verify that there are correct.
+void ImGui::DebugTextEncoding(const char* str)
 {
-    ImGui::TableNextColumn();
+    Text("Text: \"%s\"", str);
-    if (font->FindGlyphNoFallback(c))
+    if (!BeginTable("list", 4, ImGuiTableFlags_Borders | ImGuiTableFlags_RowBg | ImGuiTableFlags_SizingFixedFit))
-        ImGui::TextUnformatted(c_utf8);
+        return;
-    else
+    TableSetupColumn("Offset");
-        ImGui::TextColored(ImVec4(1.0f, 0.0f, 0.0f, 1.0f), "(not in font)");
+    TableSetupColumn("UTF-8");
-
+    TableSetupColumn("Glyph");
-    ImGui::TableNextColumn();
+    TableSetupColumn("Codepoint");
-    char utf8_code[] = "0x.. 0x.. 0x.. 0x..";
+    TableHeadersRow();
-    for (int byte_index = 0; c_utf8[byte_index]; byte_index++)
+    for (const char* p = str; *p != 0; )
-    {
-        if (byte_index > 0)
-            utf8_code[byte_index * 5 - 1] = ' ';
-        ImFormatString(utf8_code + (byte_index * 5) + 2, 3, "%02X", (int)(unsigned char)c_utf8[byte_index]);
-    }
-    ImGui::TextUnformatted(utf8_code);
-    ImGui::TableNextColumn();
-    ImGui::Text("U+%04X", (int)c);
-}
-
-static void ShowUTF8EncodingViewer()
-{
-    static char buf[256] = "";
-    static ImFontGlyphRangesBuilder range_builder;
-    static ImVector<ImWchar> ranges;
-    static bool unique_glyphs = false;
-
-    ImGui::SetNextItemWidth(-FLT_MIN);
-
-    bool rebuild = false;
-    rebuild |= ImGui::InputText("##Sample Text", buf, IM_ARRAYSIZE(buf));
-    rebuild |= ImGui::Checkbox("Sorted unique glyphs", &unique_glyphs);
-    if (rebuild && unique_glyphs)
-    {
-        range_builder.Clear();
-        range_builder.AddText(buf);
-        ranges.clear();
-        range_builder.BuildRanges(&ranges);
-    }
-    if (ImGui::BeginTable("list", 3, ImGuiTableFlags_Borders | ImGuiTableFlags_ScrollY, ImVec2(0.0f, ImGui::GetFontSize() * 15)))
-    {
-        ImGui::TableSetupColumn("Glyph");
-        ImGui::TableSetupColumn("UTF-8");
-        ImGui::TableSetupColumn("Codepoint");
-        ImGui::TableHeadersRow();
-
-        ImFont* font = ImGui::GetFont();
-        if (unique_glyphs)
-        {
-            for (int range_index = 0; range_index < ranges.Size && ranges[range_index] != 0; range_index += 2)
-                for (ImWchar c = ranges[range_index]; c <= ranges[range_index + 1]; c++)
-                {
-                    char c_utf8[4 + 1];
-                    ImTextStrToUtf8(c_utf8, IM_ARRAYSIZE(c_utf8), &c, &c + 1);
-                    ShowEncodingViewerChar(font, c, c_utf8);
-                }
-        }
-        else
-        {
-            for (const char* p = buf; p[0] != 0;)
     {
         unsigned int c;
-                int c_utf8_len = ImTextCharFromUtf8(&c, p, NULL);
+        const int c_utf8_len = ImTextCharFromUtf8(&c, p, NULL);
-                char c_utf8[4 + 1];
+        TableNextColumn();
-                memcpy(c_utf8, p, c_utf8_len);
+        Text("%d", (int)(p - str));
-                c_utf8[c_utf8_len] = 0;
+        TableNextColumn();
-                ShowEncodingViewerChar(font, (ImWchar)c, c_utf8);
+        for (int byte_index = 0; byte_index < c_utf8_len; byte_index++)
+        {
+            if (byte_index > 0)
+                SameLine();
+            Text("0x%02X", (int)(unsigned char)p[byte_index]);
+        }
+        TableNextColumn();
+        if (GetFont()->FindGlyphNoFallback((ImWchar)c))
+            TextUnformatted(p, p + c_utf8_len);
+        else
+            TextUnformatted("[missing]");
+        TableNextColumn();
+        Text("U+%04X", (int)c);
         p += c_utf8_len;
     }
-        }
+    EndTable();
-        ImGui::EndTable();
-    }
 }
 
 // Avoid naming collision with imgui_demo.cpp's HelpMarker() for unity builds.
@@ -12216,9 +12181,24 @@ static void MetricsHelpMarker(const char* desc)
     }
 }
 
-#ifndef IMGUI_DISABLE_DEMO_WINDOWS
+// [DEBUG] List fonts in a font atlas and display its texture
-namespace ImGui { void ShowFontAtlas(ImFontAtlas* atlas); }
+void ImGui::ShowFontAtlas(ImFontAtlas* atlas)
-#endif
+{
+    for (int i = 0; i < atlas->Fonts.Size; i++)
+    {
+        ImFont* font = atlas->Fonts[i];
+        PushID(font);
+        DebugNodeFont(font);
+        PopID();
+    }
+    if (TreeNode("Atlas texture", "Atlas texture (%dx%d pixels)", atlas->TexWidth, atlas->TexHeight))
+    {
+        ImVec4 tint_col = ImVec4(1.0f, 1.0f, 1.0f, 1.0f);
+        ImVec4 border_col = ImVec4(1.0f, 1.0f, 1.0f, 0.5f);
+        Image(atlas->TexID, ImVec2((float)atlas->TexWidth, (float)atlas->TexHeight), ImVec2(0.0f, 0.0f), ImVec2(1.0f, 1.0f), tint_col, border_col);
+        TreePop();
+    }
+}
 
 void ImGui::ShowMetricsWindow(bool* p_open)
 {
@@ -12293,6 +12273,19 @@ void ImGui::ShowMetricsWindow(bool* p_open)
     // Tools
     if (TreeNode("Tools"))
     {
+        bool show_encoding_viewer = TreeNode("UTF-8 Encoding viewer");
+        SameLine();
+        MetricsHelpMarker("You can also call ImGui::DebugTextEncoding() from your code with a given string to test that your UTF-8 encoding settings are correct.");
+        if (show_encoding_viewer)
+        {
+            static char buf[100] = "";
+            SetNextItemWidth(-FLT_MIN);
+            InputText("##Text", buf, IM_ARRAYSIZE(buf));
+            if (buf[0] != 0)
+                DebugTextEncoding(buf);
+            TreePop();
+        }
+
         // Stack Tool is your best friend!
         Checkbox("Show stack tool", &cfg->ShowStackTool);
         SameLine();
@@ -12360,12 +12353,6 @@ void ImGui::ShowMetricsWindow(bool* p_open)
             }
         }
 
-        if (TreeNode("UTF-8 Encoding viewer"))
-        {
-            ShowUTF8EncodingViewer();
-            TreePop();
-        }
-
         // The Item Picker tool is super useful to visually select an item and break into the call-stack of where it was submitted.
         if (Button("Item Picker.."))
             DebugStartItemPicker();
@@ -12461,14 +12448,12 @@ void ImGui::ShowMetricsWindow(bool* p_open)
     }
 
     // Details for Fonts
-#ifndef IMGUI_DISABLE_DEMO_WINDOWS
     ImFontAtlas* atlas = g.IO.Fonts;
     if (TreeNode("Fonts", "Fonts (%d)", atlas->Fonts.Size))
     {
         ShowFontAtlas(atlas);
         TreePop();
     }
-#endif
 
     // Details for Docking
 #ifdef IMGUI_HAS_DOCK
@@ -12628,25 +12613,6 @@ void ImGui::ShowMetricsWindow(bool* p_open)
     End();
 }
 
-// [DEBUG] List fonts in a font atlas and display its texture
-void ImGui::ShowFontAtlas(ImFontAtlas* atlas)
-{
-    for (int i = 0; i < atlas->Fonts.Size; i++)
-    {
-        ImFont* font = atlas->Fonts[i];
-        PushID(font);
-        DebugNodeFont(font);
-        PopID();
-    }
-    if (TreeNode("Atlas texture", "Atlas texture (%dx%d pixels)", atlas->TexWidth, atlas->TexHeight))
-    {
-        ImVec4 tint_col = ImVec4(1.0f, 1.0f, 1.0f, 1.0f);
-        ImVec4 border_col = ImVec4(1.0f, 1.0f, 1.0f, 0.5f);
-        Image(atlas->TexID, ImVec2((float)atlas->TexWidth, (float)atlas->TexHeight), ImVec2(0.0f, 0.0f), ImVec2(1.0f, 1.0f), tint_col, border_col);
-        TreePop();
-    }
-}
-
 // [DEBUG] Display contents of Columns
 void ImGui::DebugNodeColumns(ImGuiOldColumns* columns)
 {
@@ -12856,17 +12822,13 @@ void ImGui::DebugNodeFont(ImFont* font)
                 ImVec2 cell_p2(cell_p1.x + cell_size, cell_p1.y + cell_size);
                 const ImFontGlyph* glyph = font->FindGlyphNoFallback((ImWchar)(base + n));
                 draw_list->AddRect(cell_p1, cell_p2, glyph ? IM_COL32(255, 255, 255, 100) : IM_COL32(255, 255, 255, 50));
-                if (glyph)
+                if (!glyph)
+                    continue;
                 font->RenderChar(draw_list, cell_size, cell_p1, glyph_col, (ImWchar)(base + n));
-                if (glyph && IsMouseHoveringRect(cell_p1, cell_p2))
+                if (IsMouseHoveringRect(cell_p1, cell_p2))
                 {
                     BeginTooltip();
-                    Text("Codepoint: U+%04X", base + n);
+                    DebugNodeFontGlyph(font, glyph);
-                    Separator();
-                    Text("Visible: %d", glyph->Visible);
-                    Text("AdvanceX: %.1f", glyph->AdvanceX);
-                    Text("Pos: (%.2f,%.2f)->(%.2f,%.2f)", glyph->X0, glyph->Y0, glyph->X1, glyph->Y1);
-                    Text("UV: (%.3f,%.3f)->(%.3f,%.3f)", glyph->U0, glyph->V0, glyph->U1, glyph->V1);
                     EndTooltip();
                 }
             }
@@ -12878,6 +12840,16 @@ void ImGui::DebugNodeFont(ImFont* font)
     TreePop();
 }
 
+void ImGui::DebugNodeFontGlyph(ImFont*, const ImFontGlyph* glyph)
+{
+    Text("Codepoint: U+%04X", glyph->Codepoint);
+    Separator();
+    Text("Visible: %d", glyph->Visible);
+    Text("AdvanceX: %.1f", glyph->AdvanceX);
+    Text("Pos: (%.2f,%.2f)->(%.2f,%.2f)", glyph->X0, glyph->Y0, glyph->X1, glyph->Y1);
+    Text("UV: (%.3f,%.3f)->(%.3f,%.3f)", glyph->U0, glyph->V0, glyph->U1, glyph->V1);
+}
+
 // [DEBUG] Display contents of ImGuiStorage
 void ImGui::DebugNodeStorage(ImGuiStorage* storage, const char* label)
 {

imgui.h

@@ -919,7 +919,7 @@ namespace ImGui
     IMGUI_API const char*   SaveIniSettingsToMemory(size_t* out_ini_size = NULL);               // return a zero-terminated string with the .ini data which you can save by your own mean. call when io.WantSaveIniSettings is set, then save data by your own mean and clear io.WantSaveIniSettings.
 
     // Debug Utilities
-    // - This is used by the IMGUI_CHECKVERSION() macro.
+    IMGUI_API void          DebugTextEncoding(const char* text);
     IMGUI_API bool          DebugCheckVersionAndDataLayout(const char* version_str, size_t sz_io, size_t sz_style, size_t sz_vec2, size_t sz_vec4, size_t sz_drawvert, size_t sz_drawidx); // This is called by IMGUI_CHECKVERSION() macro.
 
     // Memory Allocators

imgui_internal.h

@@ -2871,6 +2871,7 @@ namespace ImGui
     IMGUI_API void          DebugNodeDrawList(ImGuiWindow* window, const ImDrawList* draw_list, const char* label);
     IMGUI_API void          DebugNodeDrawCmdShowMeshAndBoundingBox(ImDrawList* out_draw_list, const ImDrawList* draw_list, const ImDrawCmd* draw_cmd, bool show_mesh, bool show_aabb);
     IMGUI_API void          DebugNodeFont(ImFont* font);
+    IMGUI_API void          DebugNodeFontGlyph(ImFont* font, const ImFontGlyph* glyph);
     IMGUI_API void          DebugNodeStorage(ImGuiStorage* storage, const char* label);
     IMGUI_API void          DebugNodeTabBar(ImGuiTabBar* tab_bar, const char* label);
     IMGUI_API void          DebugNodeTable(ImGuiTable* table);