qwasmbackingstore.cpp

Enable keyboard shortcuts

// Copyright (C) 2018 The Qt Company Ltd.

// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only

// Qt-Security score:significant reason:default

#include "qwasmbackingstore.h"

#include "qwasmwindow.h"

#include "qwasmcompositor.h"

#include "qwasmdom.h"

#include <QtGui/qpainter.h>

#include <QtGui/qbackingstore.h>

#include <emscripten.h>

#include <emscripten/wire.h>

QT_BEGIN_NAMESPACE

QWasmBackingStore::QWasmBackingStore(QWasmCompositor *compositor, QWindow *window)

    : QPlatformBackingStore(window), m_compositor(compositor)

    QWasmWindow *wasmWindow = static_cast<QWasmWindow *>(window->handle());

    if (wasmWindow)

        wasmWindow->setBackingStore(this);

QWasmBackingStore::~QWasmBackingStore()

    auto window = this->window();

    QWasmIntegration::get()->removeBackingStore(window);

    QWasmWindow *wasmWindow = static_cast<QWasmWindow *>(window->handle());

    if (wasmWindow)

        wasmWindow->setBackingStore(nullptr);

QPaintDevice *QWasmBackingStore::paintDevice()

    return &m_image;

void QWasmBackingStore::flush(QWindow *window, const QRegion &region, const QPoint &offset)

    Q_UNUSED(window);

    m_dirty |= region;

    QRect updateRect = region.boundingRect();

    updateRect.translate(offset);

    m_compositor->handleBackingStoreFlush(this->window(), updateRect);

void QWasmBackingStore::updateTexture(QWasmWindow *window)

    if (m_dirty.isNull())

        return;

    if (m_image.size().isEmpty())

        return;

    if (m_webImageDataArray.isUndefined()) {

        m_webImageDataArray = window->context2d().call<emscripten::val>(

                "createImageData", emscripten::val(m_image.width()),

                emscripten::val(m_image.height()));

    QRegion clippedDpiScaledRegion;

    QRect imageRect = m_image.rect();

    for (const QRect &rect : m_dirty) {

        // Convert device-independent dirty region to device region

        qreal dpr = m_image.devicePixelRatio();

        QRect deviceRect = QRect(rect.topLeft() * dpr, rect.size() * dpr);

        // intersect with image rect to be sure

        QRect r = imageRect & deviceRect;

        // if the rect is wide enough it is cheaper to just extend it instead of doing an image copy

        if (r.width() >= imageRect.width() / 2) {

            r.setX(0);

            r.setWidth(imageRect.width());

        clippedDpiScaledRegion |= r;

    for (const QRect &dirtyRect : clippedDpiScaledRegion)

        dom::drawImageToWebImageDataArray(m_image, m_webImageDataArray, dirtyRect);

    m_dirty = QRegion();

void QWasmBackingStore::beginPaint(const QRegion &region)

    m_dirty |= region;

    // Keep backing store device pixel ratio in sync with window

    if (m_image.devicePixelRatio() != window()->handle()->devicePixelRatio())

        resize(backingStore()->size(), backingStore()->staticContents());

    QPainter painter(&m_image);

    if (m_image.hasAlphaChannel()) {

        painter.setCompositionMode(QPainter::CompositionMode_Source);

        const QColor blank = Qt::transparent;

        for (const QRect &rect : region)

            painter.fillRect(rect, blank);

void QWasmBackingStore::resize(const QSize &size, const QRegion &staticContents)

    Q_UNUSED(staticContents);

    QImage::Format format = QImage::Format_RGBA8888;

    const auto platformScreenDPR = window()->handle()->devicePixelRatio();

    m_image = QImage(size * platformScreenDPR, format);

    m_image.setDevicePixelRatio(platformScreenDPR);

    m_webImageDataArray = emscripten::val::undefined();

QImage QWasmBackingStore::toImage() const

    // used by QPlatformBackingStore::rhiFlush

    return m_image;

const QImage &QWasmBackingStore::getImageRef() const

    return m_image;

emscripten::val QWasmBackingStore::getUpdatedWebImage(QWasmWindow *window)

    updateTexture(window);

    return m_webImageDataArray;

QT_END_NAMESPACE