Tables: Angled headers: added TableAngledHeadersTextAlign, ImGuiStyleVar_TableAngledHeadersTextAlign. (#6917)

docs/CHANGELOG.txt

@@ -67,6 +67,9 @@ Other changes:
 - ProgressBar: Added support for indeterminate progress bar by passing an animated
   negative fraction, e.g. ProgressBar(-1.0f * GetTime()). (#5316, #5370, #1901)[@gan74]
 - Tables: Angled headers: fixed multi-line label display when angle is flipped. (#6917)
+- Tables: Angled headers: added style.TableAngledHeadersTextAlign and corresponding
+  ImGuiStyleVar_TableAngledHeadersTextAlign variable. Default to horizontal center. (#6917)
+  [@thedmd, @ocornut]
 - Text, DrawList: Improved handling of long single-line wrapped text. Faster and
   mitigitate issues with reading vertex indexing limits with 16-bit indices. (#7496, #5720)
 - Backends: OpenGL: Detect ES3 contexts on desktop based on version string,

imgui.cpp

@@ -1226,6 +1226,7 @@ ImGuiStyle::ImGuiStyle()
     TabMinWidthForCloseButton = 0.0f;           // Minimum width for close button to appear on an unselected tab when hovered. Set to 0.0f to always show when hovering, set to FLT_MAX to never show close button unless selected.
     TabBarBorderSize        = 1.0f;             // Thickness of tab-bar separator, which takes on the tab active color to denote focus.
     TableAngledHeadersAngle = 35.0f * (IM_PI / 180.0f); // Angle of angled headers (supported values range from -50 degrees to +50 degrees).
+    TableAngledHeadersTextAlign = ImVec2(0.5f,0.0f); // Alignment of angled headers within the cell
     ColorButtonPosition     = ImGuiDir_Right;   // Side of the color button in the ColorEdit4 widget (left/right). Defaults to ImGuiDir_Right.
     ButtonTextAlign         = ImVec2(0.5f,0.5f);// Alignment of button text when button is larger than text.
     SelectableTextAlign     = ImVec2(0.0f,0.0f);// Alignment of selectable text. Defaults to (0.0f, 0.0f) (top-left aligned). It's generally important to keep this left-aligned if you want to lay multiple items on a same line.
@@ -3156,6 +3157,7 @@ static const ImGuiDataVarInfo GStyleVarInfo[] =
     { ImGuiDataType_Float, 1, (ImU32)offsetof(ImGuiStyle, TabBorderSize) },         // ImGuiStyleVar_TabBorderSize
     { ImGuiDataType_Float, 1, (ImU32)offsetof(ImGuiStyle, TabBarBorderSize) },      // ImGuiStyleVar_TabBarBorderSize
     { ImGuiDataType_Float, 1, (ImU32)offsetof(ImGuiStyle, TableAngledHeadersAngle)},// ImGuiStyleVar_TableAngledHeadersAngle
+    { ImGuiDataType_Float, 2, (ImU32)offsetof(ImGuiStyle, TableAngledHeadersTextAlign)},//ImGuiStyleVar_TableAngledHeadersTextAlign
     { ImGuiDataType_Float, 2, (ImU32)offsetof(ImGuiStyle, ButtonTextAlign) },       // ImGuiStyleVar_ButtonTextAlign
     { ImGuiDataType_Float, 2, (ImU32)offsetof(ImGuiStyle, SelectableTextAlign) },   // ImGuiStyleVar_SelectableTextAlign
     { ImGuiDataType_Float, 1, (ImU32)offsetof(ImGuiStyle, SeparatorTextBorderSize)},// ImGuiStyleVar_SeparatorTextBorderSize

imgui.h

@@ -1584,6 +1584,7 @@ enum ImGuiStyleVar_
     ImGuiStyleVar_TabBorderSize,       // float     TabBorderSize
     ImGuiStyleVar_TabBarBorderSize,    // float     TabBarBorderSize
     ImGuiStyleVar_TableAngledHeadersAngle,// float  TableAngledHeadersAngle
+    ImGuiStyleVar_TableAngledHeadersTextAlign,// ImVec2 TableAngledHeadersTextAlign
     ImGuiStyleVar_ButtonTextAlign,     // ImVec2    ButtonTextAlign
     ImGuiStyleVar_SelectableTextAlign, // ImVec2    SelectableTextAlign
     ImGuiStyleVar_SeparatorTextBorderSize,// float  SeparatorTextBorderSize
@@ -2017,6 +2018,7 @@ struct ImGuiStyle
     float       TabMinWidthForCloseButton;  // Minimum width for close button to appear on an unselected tab when hovered. Set to 0.0f to always show when hovering, set to FLT_MAX to never show close button unless selected.
     float       TabBarBorderSize;           // Thickness of tab-bar separator, which takes on the tab active color to denote focus.
     float       TableAngledHeadersAngle;    // Angle of angled headers (supported values range from -50.0f degrees to +50.0f degrees).
+    ImVec2      TableAngledHeadersTextAlign;// Alignment of angled headers within the cell
     ImGuiDir    ColorButtonPosition;        // Side of the color button in the ColorEdit4 widget (left/right). Defaults to ImGuiDir_Right.
     ImVec2      ButtonTextAlign;            // Alignment of button text when button is larger than text. Defaults to (0.5f, 0.5f) (centered).
     ImVec2      SelectableTextAlign;        // Alignment of selectable text. Defaults to (0.0f, 0.0f) (top-left aligned). It's generally important to keep this left-aligned if you want to lay multiple items on a same line.

imgui_demo.cpp

@@ -5353,6 +5353,17 @@ static void ShowDemoWindowTables()
         ImGui::SliderInt("Frozen rows", &frozen_rows, 0, 2);
         ImGui::CheckboxFlags("Disable header contributing to column width", &column_flags, ImGuiTableColumnFlags_NoHeaderWidth);
 
+        if (ImGui::TreeNode("Style settings"))
+        {
+            ImGui::SameLine();
+            HelpMarker("Giving access to some ImGuiStyle value in this demo for convenience.");
+            ImGui::SetNextItemWidth(ImGui::GetFontSize() * 8);
+            ImGui::SliderAngle("style.TableAngledHeadersAngle", &ImGui::GetStyle().TableAngledHeadersAngle, -50.0f, +50.0f);
+            ImGui::SetNextItemWidth(ImGui::GetFontSize() * 8);
+            ImGui::SliderFloat2("style.TableAngledHeadersTextAlign", (float*)&ImGui::GetStyle().TableAngledHeadersTextAlign, 0.0f, 1.0f, "%.2f");
+            ImGui::TreePop();
+        }
+
         if (ImGui::BeginTable("table_angled_headers", columns_count, table_flags, ImVec2(0.0f, TEXT_BASE_HEIGHT * 12)))
         {
             ImGui::TableSetupColumn(column_names[0], ImGuiTableColumnFlags_NoHide | ImGuiTableColumnFlags_NoReorder);
@@ -6642,6 +6653,7 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
             ImGui::SeparatorText("Tables");
             ImGui::SliderFloat2("CellPadding", (float*)&style.CellPadding, 0.0f, 20.0f, "%.0f");
             ImGui::SliderAngle("TableAngledHeadersAngle", &style.TableAngledHeadersAngle, -50.0f, +50.0f);
+            ImGui::SliderFloat2("TableAngledHeadersTextAlign", (float*)&style.TableAngledHeadersTextAlign, 0.0f, 1.0f, "%.2f");
 
             ImGui::SeparatorText("Widgets");
             ImGui::SliderFloat2("WindowTitleAlign", (float*)&style.WindowTitleAlign, 0.0f, 1.0f, "%.2f");

imgui_tables.cpp

@@ -3252,9 +3252,13 @@ void ImGui::TableAngledHeadersRowEx(ImGuiID row_id, float angle, float max_label
     ButtonBehavior(row_r, row_id, NULL, NULL);
     KeepAliveID(row_id);
 
+    const float ascent_scaled = g.Font->Ascent * (g.FontSize / g.Font->FontSize); // FIXME: Standardize those scaling factors better
+    const float line_off_for_ascent_x = (ImMax((g.FontSize - ascent_scaled) * 0.5f, 0.0f) / -sin_a) * (flip_label ? -1.0f : 1.0f);
+    const ImVec2 padding = g.Style.CellPadding; // We will always use swapped component
+    const ImVec2 align = g.Style.TableAngledHeadersTextAlign;
+
     // Draw background and labels in first pass, then all borders.
     float max_x = 0.0f;
-    ImVec2 padding = g.Style.CellPadding; // We will always use swapped component
     for (int pass = 0; pass < 2; pass++)
         for (int order_n = 0; order_n < data_count; order_n++)
         {
@@ -3279,8 +3283,17 @@ void ImGui::TableAngledHeadersRowEx(ImGuiID row_id, float angle, float max_label
                 // - Handle multiple lines manually, as we want each lines to follow on the horizontal border, rather than see a whole block rotated.
                 const char* label_name = TableGetColumnName(table, column_n);
                 const char* label_name_end = FindRenderedTextEnd(label_name);
-                const float line_off_step_x = (g.FontSize / -sin_a) * (flip_label ? -1.0f : 1.0f);
-                float line_off_curr_x = flip_label ? (ImTextCountLines(label_name, label_name_end) - 1) * -line_off_step_x : 0.0f;
+                const float line_off_step_x = (g.FontSize / -sin_a);
+                const int label_lines = ImTextCountLines(label_name, label_name_end);
+
+                // Left<>Right alignment
+                float line_off_curr_x = flip_label ? (label_lines - 1) * line_off_step_x : 0.0f;
+                float line_off_for_align_x = ImMax((((column->MaxX - column->MinX) - padding.x * 2.0f) - (label_lines * line_off_step_x)), 0.0f) * align.x;
+                line_off_curr_x += line_off_for_align_x - line_off_for_ascent_x;
+
+                // Register header width
+                column->ContentMaxXHeadersUsed = column->ContentMaxXHeadersIdeal = column->WorkMinX + ImCeil(label_lines * line_off_step_x - line_off_for_align_x);
+
                 while (label_name < label_name_end)
                 {
                     const char* label_name_eol = strchr(label_name, '\n');
@@ -3298,19 +3311,21 @@ void ImGui::TableAngledHeadersRowEx(ImGuiID row_id, float angle, float max_label
                     PopStyleColor();
                     int vtx_idx_end = draw_list->_VtxCurrentIdx;
 
+                    // Up<>Down alignment
+                    const float available_space = ImMax(clip_width - label_size.x + ImAbs(padding.x * cos_a) * 2.0f - ImAbs(padding.y * sin_a) * 2.0f, 0.0f);
+                    const float vertical_offset = available_space * align.y * (flip_label ? -1.0f : 1.0f);
+
                     // Rotate and offset label
-                    ImVec2 pivot_in = ImVec2(window->ClipRect.Min.x, window->ClipRect.Min.y + label_size.y);
+                    ImVec2 pivot_in = ImVec2(window->ClipRect.Min.x - vertical_offset, window->ClipRect.Min.y + label_size.y);
                     ImVec2 pivot_out = ImVec2(column->WorkMinX, row_r.Max.y);
-                    line_off_curr_x += line_off_step_x;
+                    line_off_curr_x += flip_label ? -line_off_step_x : line_off_step_x;
                     pivot_out += unit_right * padding.y;
                     if (flip_label)
                         pivot_out += unit_right * (clip_width - ImMax(0.0f, clip_width - label_size.x));
-                    pivot_out.x += flip_label ? line_off_curr_x - line_off_step_x : line_off_curr_x;
+                    pivot_out.x += flip_label ? line_off_curr_x + line_off_step_x : line_off_curr_x;
                     ShadeVertsTransformPos(draw_list, vtx_idx_begin, vtx_idx_end, pivot_in, label_cos_a, label_sin_a, pivot_out); // Rotate and offset
-                    //if (g.IO.KeyShift) { ImDrawList* fg_dl = GetForegroundDrawList(); vtx_idx_begin = fg_dl->_VtxCurrentIdx; fg_dl->AddRect(clip_r.Min, clip_r.Max, IM_COL32(0, 255, 0, 255), 0.0f, 0, 2.0f); ShadeVertsTransformPos(fg_dl, vtx_idx_begin, fg_dl->_VtxCurrentIdx, pivot_in, label_cos_a, label_sin_a, pivot_out); }
+                    //if (g.IO.KeyShift) { ImDrawList* fg_dl = GetForegroundDrawList(); vtx_idx_begin = fg_dl->_VtxCurrentIdx; fg_dl->AddRect(clip_r.Min, clip_r.Max, IM_COL32(0, 255, 0, 255), 0.0f, 0, 1.0f); ShadeVertsTransformPos(fg_dl, vtx_idx_begin, fg_dl->_VtxCurrentIdx, pivot_in, label_cos_a, label_sin_a, pivot_out); }
 
-                    // Register header width
-                    column->ContentMaxXHeadersUsed = column->ContentMaxXHeadersIdeal = column->WorkMinX + ImCeil(line_off_curr_x);
                     label_name = label_name_eol + 1;
                 }
             }