InputText: added ImGuiInputTextFlags_ElideLeft. (ocornut#1442, ocornut#1440, ocornut#4391, ocornut#7208, ocornut#8216)

Author: ocornut

docs/CHANGELOG.txt

@@ -58,6 +58,9 @@ Other changes:
   processing errors outside of the NewFrame()..EndFrame() scope. (#1651)
 - Tables: fixed SetNextWindowScroll() value being ignored by BeginTable() during
   the first frame or when scrolling flags have changed. (#8196)
+- InputText: added ImGuiInputTextFlags_ElideLeft to elide left side and ensure right side
+  of contents is visible when whole text is not fitting (useful for paths/filenames).
+  (#1442, #1440, #4391, #7208, #8216) [@kucoman, @ocornut]
 - InputText: reactivating last activated InputText() doesn't restore horizontal scrolling
   (which was disabled during deactivation anyway).
 - Misc: changed embedded ProggyClean encoding to save a bit of binary space (~12kb to 9.5kb).

imgui.h

@@ -29,7 +29,7 @@
 // Library Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals, e.g. '#if IMGUI_VERSION_NUM >= 12345')
 #define IMGUI_VERSION       "1.91.6 WIP"
-#define IMGUI_VERSION_NUM   19152
+#define IMGUI_VERSION_NUM   19153
 #define IMGUI_HAS_TABLE
 
 /*
@@ -1171,13 +1171,16 @@ enum ImGuiInputTextFlags_
     ImGuiInputTextFlags_NoHorizontalScroll  = 1 << 15,  // Disable following the cursor horizontally
     ImGuiInputTextFlags_NoUndoRedo          = 1 << 16,  // Disable undo/redo. Note that input text owns the text data while active, if you want to provide your own undo/redo stack you need e.g. to call ClearActiveID().
 
+    // Elide display / Alignment
+    ImGuiInputTextFlags_ElideLeft			= 1 << 17,	// When text doesn't fit, elide left side to ensure right side stays visible. Useful for path/filenames. Single-line only!
+
     // Callback features
-    ImGuiInputTextFlags_CallbackCompletion  = 1 << 17,  // Callback on pressing TAB (for completion handling)
-    ImGuiInputTextFlags_CallbackHistory     = 1 << 18,  // Callback on pressing Up/Down arrows (for history handling)
-    ImGuiInputTextFlags_CallbackAlways      = 1 << 19,  // Callback on each iteration. User code may query cursor position, modify text buffer.
-    ImGuiInputTextFlags_CallbackCharFilter  = 1 << 20,  // Callback on character inputs to replace or discard them. Modify 'EventChar' to replace or discard, or return 1 in callback to discard.
-    ImGuiInputTextFlags_CallbackResize      = 1 << 21,  // Callback on buffer capacity changes request (beyond 'buf_size' parameter value), allowing the string to grow. Notify when the string wants to be resized (for string types which hold a cache of their Size). You will be provided a new BufSize in the callback and NEED to honor it. (see misc/cpp/imgui_stdlib.h for an example of using this)
-    ImGuiInputTextFlags_CallbackEdit        = 1 << 22,  // Callback on any edit (note that InputText() already returns true on edit, the callback is useful mainly to manipulate the underlying buffer while focus is active)
+    ImGuiInputTextFlags_CallbackCompletion  = 1 << 18,  // Callback on pressing TAB (for completion handling)
+    ImGuiInputTextFlags_CallbackHistory     = 1 << 19,  // Callback on pressing Up/Down arrows (for history handling)
+    ImGuiInputTextFlags_CallbackAlways      = 1 << 20,  // Callback on each iteration. User code may query cursor position, modify text buffer.
+    ImGuiInputTextFlags_CallbackCharFilter  = 1 << 21,  // Callback on character inputs to replace or discard them. Modify 'EventChar' to replace or discard, or return 1 in callback to discard.
+    ImGuiInputTextFlags_CallbackResize      = 1 << 22,  // Callback on buffer capacity changes request (beyond 'buf_size' parameter value), allowing the string to grow. Notify when the string wants to be resized (for string types which hold a cache of their Size). You will be provided a new BufSize in the callback and NEED to honor it. (see misc/cpp/imgui_stdlib.h for an example of using this)
+    ImGuiInputTextFlags_CallbackEdit        = 1 << 23,  // Callback on any edit (note that InputText() already returns true on edit, the callback is useful mainly to manipulate the underlying buffer while focus is active)
 
     // Obsolete names
     //ImGuiInputTextFlags_AlwaysInsertMode  = ImGuiInputTextFlags_AlwaysOverwrite   // [renamed in 1.82] name was not matching behavior

imgui_demo.cpp

@@ -1830,6 +1830,16 @@ static void ShowDemoWindowWidgets(ImGuiDemoWindowData* demo_data)
             ImGui::TreePop();
         }
 
+        IMGUI_DEMO_MARKER("Widgets/Text Input/Eliding, Alignment");
+        if (ImGui::TreeNode("Eliding, Alignment"))
+        {
+            static char buf1[128] = "/path/to/some/folder/with/long/filename.cpp";
+            static ImGuiInputTextFlags flags = ImGuiInputTextFlags_ElideLeft;
+            ImGui::CheckboxFlags("ImGuiInputTextFlags_ElideLeft", &flags, ImGuiInputTextFlags_ElideLeft);
+            ImGui::InputText("Path", buf1, IM_ARRAYSIZE(buf1), flags);
+            ImGui::TreePop();
+        }
+
         IMGUI_DEMO_MARKER("Widgets/Text Input/Miscellaneous");
         if (ImGui::TreeNode("Miscellaneous"))
         {

imgui_widgets.cpp

@@ -4403,6 +4403,7 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
     IM_ASSERT(buf != NULL && buf_size >= 0);
     IM_ASSERT(!((flags & ImGuiInputTextFlags_CallbackHistory) && (flags & ImGuiInputTextFlags_Multiline)));        // Can't use both together (they both use up/down keys)
     IM_ASSERT(!((flags & ImGuiInputTextFlags_CallbackCompletion) && (flags & ImGuiInputTextFlags_AllowTabInput))); // Can't use both together (they both use tab key)
+    IM_ASSERT(!((flags & ImGuiInputTextFlags_ElideLeft) && (flags & ImGuiInputTextFlags_Multiline)));               // Multiline will not work with left-trimming
 
     ImGuiContext& g = *GImGui;
     ImGuiIO& io = g.IO;
@@ -4537,7 +4538,11 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
         state->TextA.resize(buf_size + 1);          // we use +1 to make sure that .Data is always pointing to at least an empty string.
         state->TextLen = (int)strlen(buf);
         memcpy(state->TextA.Data, buf, state->TextLen + 1);
+
+        // Find initial scroll position for right alignment
         state->Scroll = ImVec2(0.0f, 0.0f);
+        if (flags & ImGuiInputTextFlags_ElideLeft)
+            state->Scroll.x += ImMax(0.0f, CalcTextSize(buf).x - frame_size.x + style.FramePadding.x * 2.0f);
 
         if (recycle_state)
         {
@@ -5287,6 +5292,10 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
 
         if (is_multiline || (buf_display_end - buf_display) < buf_display_max_length)
         {
+            // Find render position for right alignment
+            if (flags & ImGuiInputTextFlags_ElideLeft)
+                draw_pos.x = ImMin(draw_pos.x, frame_bb.Max.x - CalcTextSize(buf_display, NULL).x - style.FramePadding.x);
+
             const ImVec2 draw_scroll = /*state ? ImVec2(state->Scroll.x, 0.0f) :*/ ImVec2(0.0f, 0.0f); // Preserve scroll when inactive?
             ImU32 col = GetColorU32(is_displaying_hint ? ImGuiCol_TextDisabled : ImGuiCol_Text);
             draw_window->DrawList->AddText(g.Font, g.FontSize, draw_pos - draw_scroll, col, buf_display, buf_display_end, 0.0f, is_multiline ? NULL : &clip_rect);