fix: DragRect resizing when its size is zero (#661)

Author: JunkyoLee

implot.cpp

@@ -4102,31 +4102,34 @@ bool DragRect(int n_id, double* x_min, double* y_min, double* x_max, double* y_m
 
     bool modified = false;
     bool clicked = false, hovered = false, held = false;
-    ImRect b_rect(pc.x-DRAG_GRAB_HALF_SIZE,pc.y-DRAG_GRAB_HALF_SIZE,pc.x+DRAG_GRAB_HALF_SIZE,pc.y+DRAG_GRAB_HALF_SIZE);
 
-    ImGui::KeepAliveID(id);
-    if (input) {
-        // middle point
-        clicked = ImGui::ButtonBehavior(b_rect,id,&hovered,&held);
-        if (out_clicked) *out_clicked = clicked;
-        if (out_hovered) *out_hovered = hovered;
-        if (out_held)    *out_held    = held;
-    }
+    const bool is_movable = *x_min != *x_max || *y_min != *y_max;
+    if (is_movable) {
+        ImGui::KeepAliveID(id);
+        if (input) {
+            // middle point
+            ImRect b_rect(pc.x-DRAG_GRAB_HALF_SIZE,pc.y-DRAG_GRAB_HALF_SIZE,pc.x+DRAG_GRAB_HALF_SIZE,pc.y+DRAG_GRAB_HALF_SIZE);
+            clicked = ImGui::ButtonBehavior(b_rect,id,&hovered,&held);
+            if (out_clicked) *out_clicked = clicked;
+            if (out_hovered) *out_hovered = hovered;
+            if (out_held)    *out_held    = held;
+        }
 
-    if ((hovered || held) && show_curs)
-        ImGui::SetMouseCursor(ImGuiMouseCursor_ResizeAll);
-    if (held && ImGui::IsMouseDragging(0)) {
-        for (int i = 0; i < 4; ++i) {
-            ImPlotPoint pp = PixelsToPlot(p[i] + ImGui::GetIO().MouseDelta,IMPLOT_AUTO,IMPLOT_AUTO);
-            *y[i] = pp.y;
-            *x[i] = pp.x;
+        if ((hovered || held) && show_curs)
+            ImGui::SetMouseCursor(ImGuiMouseCursor_ResizeAll);
+        if (held && ImGui::IsMouseDragging(0)) {
+            for (int i = 0; i < 4; ++i) {
+                ImPlotPoint pp = PixelsToPlot(p[i] + ImGui::GetIO().MouseDelta,IMPLOT_AUTO,IMPLOT_AUTO);
+                *y[i] = pp.y;
+                *x[i] = pp.x;
+            }
+            modified = true;
         }
-        modified = true;
     }
 
     for (int i = 0; i < 4; ++i) {
         // points
-        b_rect = ImRect(p[i].x-DRAG_GRAB_HALF_SIZE,p[i].y-DRAG_GRAB_HALF_SIZE,p[i].x+DRAG_GRAB_HALF_SIZE,p[i].y+DRAG_GRAB_HALF_SIZE);
+        ImRect b_rect(p[i].x - DRAG_GRAB_HALF_SIZE, p[i].y - DRAG_GRAB_HALF_SIZE, p[i].x + DRAG_GRAB_HALF_SIZE, p[i].y + DRAG_GRAB_HALF_SIZE);
         ImGuiID p_id = id + i + 1;
         ImGui::KeepAliveID(p_id);
         if (input) {