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martincapellomartincapello
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Introduce drag and drop handling
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9 files changed

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-6
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9 files changed

+582
-6
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‎examples/CMakeLists.txt

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@@ -16,6 +16,7 @@ if(LAF_BACKEND STREQUAL "skia")
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laf_add_example(base64 CONSOLE)
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laf_add_example(complextextlayout GUI)
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laf_add_example(custom_window GUI)
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laf_add_example(drag_and_drop GUI)
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laf_add_example(floating_window GUI)
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laf_add_example(helloworld GUI)
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laf_add_example(listfonts CONSOLE)

‎examples/drag_and_drop.cpp

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// LAF Library
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// Copyright (c) 2024 Igara Studio S.A.
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//
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// This file is released under the terms of the MIT license.
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// Read LICENSE.txt for more information.
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#include "base/paths.h"
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#include "gfx/hsv.h"
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#include "gfx/rect.h"
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#include "gfx/rgb.h"
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#include "os/dnd.h"
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#include "os/draw_text.h"
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#include "os/os.h"
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#include <algorithm>
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#include <cstdarg>
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#include <cstdio>
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#include <map>
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#include <memory>
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#include <vector>
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using Boxes = std::vector<gfx::Rect>;
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struct WindowData {
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Boxes boxes;
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bool dragEnter;
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bool dragLeave;
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int drag;
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bool acceptDrop = true;
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base::paths paths;
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};
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static std::map<const os::Window*, WindowData> windowData;
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static void redraw_window(os::Window* window);
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class DragTarget : public os::DragTarget {
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public:
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DragTarget(const os::WindowRef& window) : m_window(window) {
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}
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void dragEnter(os::DragEvent& ev) override {
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auto& data = windowData[ev.target()];
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if (!data.acceptDrop || !ev.sourceSupports(os::DropOperation::Copy))
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ev.dropResult(os::DropOperation::None);
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else if (ev.sourceSupports(os::DropOperation::Copy))
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ev.dropResult(os::DropOperation::Copy);
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data.dragEnter = true;
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data.dragLeave = false;
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data.drag = 0;
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redraw_window(ev.target());
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ev.target()->invalidate();
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}
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void dragLeave(os::DragEvent& ev) override {
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auto& data = windowData[ev.target()];
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data.dragEnter = false;
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data.dragLeave = true;
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redraw_window(ev.target());
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ev.target()->invalidate();
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}
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void drag(os::DragEvent& ev) override {
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++windowData[ev.target()].drag;
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redraw_window(ev.target());
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ev.target()->invalidate();
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}
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void drop(os::DragEvent& ev) override {
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auto& data = windowData[ev.target()];
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data.dragEnter = false;
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data.dragLeave = false;
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if (data.acceptDrop)
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data.paths = ev.data()->getItems<os::DragDataItemType::Paths>()[0];
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ev.acceptDrop(data.acceptDrop);
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redraw_window(ev.target());
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ev.target()->invalidate();
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}
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private:
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os::WindowRef m_window;
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};
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class DragSource : public os::DragSource {
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public:
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};
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static os::WindowRef windowA;
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static os::WindowRef windowB;
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const char* lines[] = {
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"T: Enable/disable acting as drag and drop target",
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"S: Enable/disable acting as drag and drop source",
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"A: Accept drop switch",
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};
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static void redraw_window(os::Window* window)
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{
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os::Surface* s = window->surface();
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os::Paint paint;
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paint.color(gfx::rgba(0, 0, 0));
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s->drawRect(window->bounds(), paint);
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paint.color(gfx::rgba(255, 255, 255));
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char buf[256];
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int y = 12;
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for (auto line : lines) {
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y += 12;
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os::draw_text(s, nullptr, line, gfx::Point(0, y), &paint);
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}
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const WindowData& data = windowData[window];
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y += 12;
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std::snprintf(buf, sizeof(buf), "Drag Enter = %s", data.dragEnter ? "true" : "false");
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os::draw_text(s, nullptr, buf, gfx::Point(0, y), &paint);
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y += 12;
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std::snprintf(buf, sizeof(buf), "Drag = %d", data.drag);
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os::draw_text(s, nullptr, buf, gfx::Point(0, y), &paint);
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y += 12;
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std::snprintf(buf, sizeof(buf), "Drag Leave = %s", data.dragLeave ? "true" : "false");
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os::draw_text(s, nullptr, buf, gfx::Point(0, y), &paint);
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y += 12;
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std::snprintf(buf, sizeof(buf), "Accept drop = %s", data.acceptDrop ? "true" : "false");
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os::draw_text(s, nullptr, buf, gfx::Point(0, y), &paint);
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if (!data.paths.empty()) {
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y += 12;
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std::snprintf(buf, sizeof(buf), "Paths = %lu", data.paths.size());
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os::draw_text(s, nullptr, buf, gfx::Point(0, y), &paint);
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for (const auto& path : data.paths) {
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y += 12;
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std::snprintf(buf, sizeof(buf), "%s", path.c_str());
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os::draw_text(s, nullptr, buf, gfx::Point(12, y), &paint);
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}
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}
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paint.style(os::Paint::Style::Stroke);
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s->drawRect(window->bounds(), paint);
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paint.color(gfx::rgba(100, 255, 100));
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for (const auto& box : data.boxes) {
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paint.style(os::Paint::Style::Stroke);
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s->drawRect(box, paint);
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paint.style(os::Paint::Style::Fill);
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os::draw_text(s, nullptr, "Drag me!", box.center(), &paint, os::TextAlign::Center);
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}
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}
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static void create_box(const os::Window* window, const gfx::Rect& box)
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{
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windowData[window].boxes.push_back(box);
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}
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static os::WindowRef create_window(const std::string& title,
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const os::WindowSpec& spec,
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const std::vector<gfx::Rect>& initialBoxes)
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{
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os::WindowRef newWindow = os::instance()->makeWindow(spec);
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newWindow->setCursor(os::NativeCursor::Arrow);
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newWindow->setTitle(title);
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newWindow->setVisible(true);
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newWindow->setDragTarget(std::make_unique<DragTarget>(newWindow));
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for (const auto& box : initialBoxes) {
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create_box(newWindow.get(), box);
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}
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redraw_window(newWindow.get());
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return newWindow;
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}
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int app_main(int argc, char* argv[])
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{
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auto system = os::make_system();
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system->setAppMode(os::AppMode::GUI);
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system->handleWindowResize = redraw_window;
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// Create two windows that can act as Drag and Drop target and/or source.
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auto screen = system->mainScreen();
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os::WindowSpec spec;
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spec.titled(true);
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spec.position(os::WindowSpec::Position::Frame);
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auto frame = screen->workarea()/2;
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spec.frame(frame);
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spec.screen(screen);
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windowA = create_window("A", spec, {{32, frame.h - 64 - 40, 64, 64}});
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frame.offset(frame.w, 0);
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spec.frame(frame);
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windowB = create_window("B", spec, {});
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bool running = true;
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system->finishLaunching();
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system->activateApp();
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os::EventQueue* queue = system->eventQueue();
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os::Event ev;
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while (running) {
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queue->getEvent(ev);
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switch (ev.type()) {
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case os::Event::CloseApp:
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case os::Event::CloseWindow:
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running = false;
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break;
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case os::Event::ResizeWindow:
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redraw_window(ev.window().get());
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ev.window()->invalidate();
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break;
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case os::Event::KeyDown:
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switch (ev.scancode()) {
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case os::kKeyT:
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break;
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case os::kKeyS:
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break;
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case os::kKeyA:
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windowData[ev.window().get()].acceptDrop = !windowData[ev.window().get()].acceptDrop;
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redraw_window(ev.window().get());
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ev.window()->invalidate();
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break;
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}
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break;
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default:
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// Do nothing
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break;
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}
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}
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return 0;
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}

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