Internals: Added SetNextWindowScroll() (#1526)

imgui.cpp

@@ -5488,6 +5488,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         UpdateWindowParentAndRootLinks(window, flags, parent_window);
 
     // Process SetNextWindow***() calls
+    // (FIXME: Consider splitting the HasXXX flags into X/Y components
     bool window_pos_set_by_api = false;
     bool window_size_x_set_by_api = false, window_size_y_set_by_api = false;
     if (g.NextWindowData.Flags & ImGuiNextWindowDataFlags_HasPos)
@@ -5512,6 +5513,19 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         window_size_y_set_by_api = (window->SetWindowSizeAllowFlags & g.NextWindowData.SizeCond) != 0 && (g.NextWindowData.SizeVal.y > 0.0f);
         SetWindowSize(window, g.NextWindowData.SizeVal, g.NextWindowData.SizeCond);
     }
+    if (g.NextWindowData.Flags & ImGuiNextWindowDataFlags_HasScroll)
+    {
+        if (g.NextWindowData.ScrollVal.x >= 0.0f)
+        {
+            window->ScrollTarget.x = g.NextWindowData.ScrollVal.x;
+            window->ScrollTargetCenterRatio.x = 0.0f;
+        }
+        if (g.NextWindowData.ScrollVal.y >= 0.0f)
+        {
+            window->ScrollTarget.y = g.NextWindowData.ScrollVal.y;
+            window->ScrollTargetCenterRatio.y = 0.0f;
+        }
+    }
     if (g.NextWindowData.Flags & ImGuiNextWindowDataFlags_HasContentSize)
         window->ContentSizeExplicit = g.NextWindowData.ContentSizeVal;
     else if (first_begin_of_the_frame)
@@ -6513,6 +6527,13 @@ void ImGui::SetNextWindowContentSize(const ImVec2& size)
     g.NextWindowData.ContentSizeVal = size;
 }
 
+void ImGui::SetNextWindowScroll(const ImVec2& scroll)
+{
+    ImGuiContext& g = *GImGui;
+    g.NextWindowData.Flags |= ImGuiNextWindowDataFlags_HasScroll;
+    g.NextWindowData.ScrollVal = scroll;
+}
+
 void ImGui::SetNextWindowCollapsed(bool collapsed, ImGuiCond cond)
 {
     ImGuiContext& g = *GImGui;

imgui_internal.h

@@ -948,7 +948,8 @@ enum ImGuiNextWindowDataFlags_
     ImGuiNextWindowDataFlags_HasCollapsed       = 1 << 3,
     ImGuiNextWindowDataFlags_HasSizeConstraint  = 1 << 4,
     ImGuiNextWindowDataFlags_HasFocus           = 1 << 5,
-    ImGuiNextWindowDataFlags_HasBgAlpha         = 1 << 6
+    ImGuiNextWindowDataFlags_HasBgAlpha         = 1 << 6,
+    ImGuiNextWindowDataFlags_HasScroll          = 1 << 7
 };
 
 // Storage for SetNexWindow** functions
@@ -962,6 +963,7 @@ struct ImGuiNextWindowData
     ImVec2                      PosPivotVal;
     ImVec2                      SizeVal;
     ImVec2                      ContentSizeVal;
+    ImVec2                      ScrollVal;
     bool                        CollapsedVal;
     ImRect                      SizeConstraintRect;
     ImGuiSizeCallback           SizeCallback;
@@ -1703,6 +1705,7 @@ namespace ImGui
     IMGUI_API ImGuiSettingsHandler* FindSettingsHandler(const char* type_name);
 
     // Scrolling
+    IMGUI_API void          SetNextWindowScroll(const ImVec2& scroll); // Use -1.0f on one axis to leave as-is
     IMGUI_API void          SetScrollX(ImGuiWindow* window, float new_scroll_x);
     IMGUI_API void          SetScrollY(ImGuiWindow* window, float new_scroll_y);
     IMGUI_API void          SetScrollFromPosX(ImGuiWindow* window, float local_x, float center_x_ratio = 0.5f);