50 lines
2 KiB
C++
50 lines
2 KiB
C++
/*
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Crafter®.Graphics
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Copyright (C) 2026 Catcrafts®
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catcrafts.net
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License version 3.0 as published by the Free Software Foundation;
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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export module Crafter.Graphics:UIHit;
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import std;
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import :UILength;
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import :UIWidget;
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export namespace Crafter::UI {
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// Find the topmost widget whose computedRect contains (x, y).
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// Children are visited in reverse order so later children (drawn on
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// top) win ties. Returns nullptr if the point is outside `root`.
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inline Widget* HitTest(Widget& root, float x, float y) {
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if (!root.computedRect.Contains(x, y)) return nullptr;
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// Search children in reverse — the last-added child is on top in
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// our draw order, so it wins overlapping hits.
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for (auto it = root.children_.rbegin(); it != root.children_.rend(); ++it) {
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if (Widget* hit = HitTest(**it, x, y); hit) return hit;
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}
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return &root;
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}
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// Dispatch a click at (x, y) to the topmost widget under the cursor,
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// bubbling to ancestors until one returns true (handled). The default
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// Widget::OnMouseClick returns false, so leaf widgets that don't care
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// automatically defer to their parents.
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inline void DispatchClick(Widget& root, float x, float y) {
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Widget* target = HitTest(root, x, y);
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while (target) {
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if (target->OnMouseClick(x, y)) return;
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target = target->parent;
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}
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}
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}
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