Add window painting testcase to the QWasmWindow test

The test checks whether windows repaint correctly by sampling the
background after their backing stores have been flushed.

Change-Id: Ib544457074d7d477a4acdc5c331ef83e5ba471d2
Reviewed-by: Piotr Wierciński <piotr.wiercinski@qt.io>
Reviewed-by: Mikołaj Boc <Mikolaj.Boc@qt.io>

tests/manual/wasm/qwasmwindow/qwasmwindow.py

@@ -24,6 +24,7 @@ class WidgetTestCase(unittest.TestCase):
         self._test_sandbox_element = WebDriverWait(self._driver, 30).until(
             presence_of_element_located((By.ID, 'test-sandbox'))
         )
+        self.addTypeEqualityFunc(Color, assert_colors_equal)
         self.addTypeEqualityFunc(Rect, assert_rects_equal)
 
     def test_window_resizing(self):
@@ -401,6 +402,33 @@ class WidgetTestCase(unittest.TestCase):
 
         self.assertFalse(w4 in screen.query_windows())
 
+    def test_window_painting(self):
+        screen = Screen(self._driver, ScreenPosition.FIXED,
+                        x=0, y=0, width=800, height=800)
+        bottom = Window(parent=screen, rect=Rect(x=0, y=0, width=400, height=400), title='root')
+        bottom.set_background_color(Color(r=255, g=0, b=0))
+        wait_for_animation_frame(self._driver)
+
+        self.assertEqual(bottom.color_at(0, 0), Color(r=255, g=0, b=0))
+
+        w1 = Window(parent=screen, rect=Rect(x=100, y=100, width=600, height=600), title='w1')
+        w1.set_background_color(Color(r=0, g=255, b=0))
+        wait_for_animation_frame(self._driver)
+
+        self.assertEqual(w1.color_at(0, 0), Color(r=0, g=255, b=0))
+
+        w1_w1 = Window(parent=w1, rect=Rect(x=100, y=100, width=400, height=400), title='w1_w1')
+        w1_w1.set_background_color(Color(r=0, g=0, b=255))
+        wait_for_animation_frame(self._driver)
+
+        self.assertEqual(w1_w1.color_at(0, 0), Color(r=0, g=0, b=255))
+
+        w1_w1_w1 = Window(parent=w1_w1, rect=Rect(x=100, y=100, width=200, height=200), title='w1_w1_w1')
+        w1_w1_w1.set_background_color(Color(r=255, g=255, b=0))
+        wait_for_animation_frame(self._driver)
+
+        self.assertEqual(w1_w1_w1.color_at(0, 0), Color(r=255, g=255, b=0))
+
     def tearDown(self):
         self._driver.quit()
 
@@ -634,6 +662,22 @@ class Window:
             '''
         )
 
+    def color_at(self, x, y):
+        raw = self.driver.execute_script(
+            f'''
+                return arguments[0].querySelector('canvas')
+                    .getContext('2d').getImageData({x}, {y}, 1, 1).data;
+            ''', self.element)
+        return Color(r=raw[0], g=raw[1], b=raw[2])
+
+    def set_background_color(self, color):
+        return self.driver.execute_script(
+            f'''
+                return instance.setWindowBackgroundColor('{self.title}', {color.r}, {color.g}, {color.b});
+            '''
+        )
+
+
 class TouchDragAction:
     def __init__(self, origin, direction):
         self.origin = origin
@@ -745,6 +789,24 @@ def call_instance_function(driver, name):
             instance.{name}();
             return eval(result);''')
 
+def wait_for_animation_frame(driver):
+    driver.execute_script(
+        '''
+            window.requestAnimationFrame(() => {
+                const sync = document.createElement('div');
+                sync.id = 'test-sync';
+                document.body.appendChild(sync);
+            });
+        '''
+    )
+    WebDriverWait(driver, 1).until(
+        presence_of_element_located((By.ID, 'test-sync'))
+    )
+    driver.execute_script(
+        '''
+            document.body.removeChild(document.body.querySelector('#test-sync'));
+        '''
+    )
 
 class Direction:
     def __init__(self):
@@ -791,6 +853,11 @@ class Handle(Enum):
     BOTTOM_RIGHT = auto()
     TOP_WINDOW_BAR = auto()
 
+class Color:
+    def __init__(self, r, g, b):
+        self.r = r
+        self.g = g
+        self.b = b
 
 class Rect:
     def __init__(self, x, y, width, height) -> None:
@@ -806,6 +873,9 @@ class Rect:
     def midpoint(self):
         return self.x + self.width / 2, self.y + self.height / 2,
 
+def assert_colors_equal(color1, color2, msg=None):
+    if color1.r != color2.r or color1.g != color2.g or color1.b != color2.b:
+        raise AssertionError(f'Colors not equal: \n{color1} \nvs \n{color2}')
 
 def assert_rects_equal(geo1, geo2, msg=None):
     if geo1.x != geo2.x or geo1.y != geo2.y or geo1.width != geo2.width or geo1.height != geo2.height:

tests/manual/wasm/qwasmwindow/qwasmwindow_harness.cpp

@@ -6,6 +6,8 @@
 #include <QtGui/qevent.h>
 #include <QtCore/qobject.h>
 #include <QtCore/qregularexpression.h>
+#include <QtGui/qpainter.h>
+#include <QtGui/qrasterwindow.h>
 #include <QtGui/qscreen.h>
 #include <QtGui/qwindow.h>
 #include <QtGui/qguiapplication.h>
@@ -18,10 +20,17 @@
 #include <sstream>
 #include <vector>
 
-class DeleteOnCloseWindow : public QWindow
+class TestWindow : public QRasterWindow
 {
     Q_OBJECT
 
+public:
+    void setBackgroundColor(int r, int g, int b)
+    {
+        m_backgroundColor = QColor::fromRgb(r, g, b);
+        update();
+    }
+
 private:
     void closeEvent(QCloseEvent *ev) override
     {
@@ -48,16 +57,24 @@ private:
         data.set("key", emscripten::val(event->text().toStdString()));
         emscripten::val::global("window")["testSupport"].call<void>("reportEvent", std::move(data));
     }
+
+    void paintEvent(QPaintEvent *e) final
+    {
+        QPainter painter(this);
+        painter.fillRect(e->rect(), m_backgroundColor);
+    }
+
+    QColor m_backgroundColor = Qt::white;
 };
 
 namespace {
-DeleteOnCloseWindow *findWindowByTitle(const std::string &title)
+TestWindow *findWindowByTitle(const std::string &title)
 {
     auto windows = qGuiApp->allWindows();
     auto window_it = std::find_if(windows.begin(), windows.end(), [&title](QWindow *window) {
         return window->title() == QString::fromLatin1(title);
     });
-    return window_it == windows.end() ? nullptr : static_cast<DeleteOnCloseWindow *>(*window_it);
+    return window_it == windows.end() ? nullptr : static_cast<TestWindow *>(*window_it);
 }
 } // namespace
 
@@ -175,7 +192,7 @@ void createWindow(int x, int y, int w, int h, std::string parentType, std::strin
         return;
     }
 
-    auto *window = new DeleteOnCloseWindow;
+    auto *window = new TestWindow;
 
     window->setFlag(Qt::WindowTitleHint);
     window->setFlag(Qt::WindowMaximizeButtonHint);
@@ -185,6 +202,16 @@ void createWindow(int x, int y, int w, int h, std::string parentType, std::strin
     window->setParent(parentWindow);
 }
 
+void setWindowBackgroundColor(std::string title, int r, int g, int b)
+{
+    auto *window = findWindowByTitle(title);
+    if (!window) {
+        qWarning() << "No such window: " << title;
+        return;
+    }
+    window->setBackgroundColor(r, g, b);
+}
+
 void setWindowVisible(int windowId, bool visible) {
     auto windows = qGuiApp->allWindows();
     auto window_it = std::find_if(windows.begin(), windows.end(), [windowId](QWindow *window) {
@@ -229,6 +256,7 @@ EMSCRIPTEN_BINDINGS(qwasmwindow)
     emscripten::function("setWindowVisible", &setWindowVisible);
     emscripten::function("setWindowParent", &setWindowParent);
     emscripten::function("closeWindow", &closeWindow);
+    emscripten::function("setWindowBackgroundColor", &setWindowBackgroundColor);
 }
 
 int main(int argc, char **argv)