summaryrefslogtreecommitdiffstats
path: root/src/plugins/platforms/windows/qwindowsbackingstore.cpp
blob: bd7bdc55d176b97bdae1d7aab39507dfae4cc7c1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the plugins of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qwindowsbackingstore.h"
#include "qwindowswindow.h"
#include "qwindowscontext.h"

#include <QtGui/qwindow.h>
#include <QtGui/qpainter.h>
#include <QtFontDatabaseSupport/private/qwindowsnativeimage_p.h>
#include <private/qhighdpiscaling_p.h>
#include <private/qimage_p.h>

#include <QtCore/qdebug.h>

QT_BEGIN_NAMESPACE

/*!
    \class QWindowsBackingStore
    \brief Backing store for windows.
    \internal
    \ingroup qt-lighthouse-win
*/

QWindowsBackingStore::QWindowsBackingStore(QWindow *window) :
    QPlatformBackingStore(window),
    m_alphaNeedsFill(false)
{
    qCDebug(lcQpaBackingStore) << __FUNCTION__ << this << window;
}

QWindowsBackingStore::~QWindowsBackingStore()
{
    qCDebug(lcQpaBackingStore) << __FUNCTION__ << this;
}

QPaintDevice *QWindowsBackingStore::paintDevice()
{
    Q_ASSERT(!m_image.isNull());
    return &m_image->image();
}

void QWindowsBackingStore::flush(QWindow *window, const QRegion &region,
                                 const QPoint &offset)
{
    Q_ASSERT(window);

    const QRect br = region.boundingRect();
    if (QWindowsContext::verbose > 1)
        qCDebug(lcQpaBackingStore) << __FUNCTION__ << this << window << offset << br;
    QWindowsWindow *rw = QWindowsWindow::windowsWindowOf(window);
    Q_ASSERT(rw);

    const bool hasAlpha = rw->format().hasAlpha();
    const Qt::WindowFlags flags = window->flags();
    if ((flags & Qt::FramelessWindowHint) && QWindowsWindow::setWindowLayered(rw->handle(), flags, hasAlpha, rw->opacity()) && hasAlpha) {
        // Windows with alpha: Use blend function to update.
        QRect r = QHighDpi::toNativePixels(window->frameGeometry(), window);
        QPoint frameOffset(QHighDpi::toNativePixels(QPoint(window->frameMargins().left(), window->frameMargins().top()),
                                                    static_cast<const QWindow *>(nullptr)));
        QRect dirtyRect = br.translated(offset + frameOffset);

        SIZE size = {r.width(), r.height()};
        POINT ptDst = {r.x(), r.y()};
        POINT ptSrc = {0, 0};
        BLENDFUNCTION blend = {AC_SRC_OVER, 0, BYTE(qRound(255.0 * rw->opacity())), AC_SRC_ALPHA};
        RECT dirty = {dirtyRect.x(), dirtyRect.y(),
                      dirtyRect.x() + dirtyRect.width(), dirtyRect.y() + dirtyRect.height()};
        UPDATELAYEREDWINDOWINFO info = {sizeof(info), nullptr, &ptDst, &size,
                                        m_image->hdc(), &ptSrc, 0, &blend, ULW_ALPHA, &dirty};
        const BOOL result = UpdateLayeredWindowIndirect(rw->handle(), &info);
        if (!result)
            qErrnoWarning("UpdateLayeredWindowIndirect failed for ptDst=(%d, %d),"
                          " size=(%dx%d), dirty=(%dx%d %d, %d)", r.x(), r.y(),
                          r.width(), r.height(), dirtyRect.width(), dirtyRect.height(),
                          dirtyRect.x(), dirtyRect.y());
    } else {
        const HDC dc = rw->getDC();
        if (!dc) {
            qErrnoWarning("%s: GetDC failed", __FUNCTION__);
            return;
        }

        if (!BitBlt(dc, br.x(), br.y(), br.width(), br.height(),
                    m_image->hdc(), br.x() + offset.x(), br.y() + offset.y(), SRCCOPY)) {
            const DWORD lastError = GetLastError(); // QTBUG-35926, QTBUG-29716: may fail after lock screen.
            if (lastError != ERROR_SUCCESS && lastError != ERROR_INVALID_HANDLE)
                qErrnoWarning(int(lastError), "%s: BitBlt failed", __FUNCTION__);
        }
        rw->releaseDC();
    }

    // Write image for debug purposes.
    if (QWindowsContext::verbose > 2 && lcQpaBackingStore().isDebugEnabled()) {
        static int n = 0;
        const QString fileName = QString::fromLatin1("win%1_%2.png").
                arg(rw->winId()).arg(n++);
        m_image->image().save(fileName);
        qCDebug(lcQpaBackingStore) << "Wrote " << m_image->image().size() << fileName;
    }
}

void QWindowsBackingStore::resize(const QSize &size, const QRegion &region)
{
    if (m_image.isNull() || m_image->image().size() != size) {
#ifndef QT_NO_DEBUG_OUTPUT
        if (QWindowsContext::verbose && lcQpaBackingStore().isDebugEnabled()) {
            qCDebug(lcQpaBackingStore)
                << __FUNCTION__ << ' ' << window() << ' ' << size << ' ' << region
                << " from: " << (m_image.isNull() ? QSize() : m_image->image().size());
        }
#endif
        QImage::Format format = window()->format().hasAlpha() ?
                    QImage::Format_ARGB32_Premultiplied : QWindowsNativeImage::systemFormat();

        // The backingstore composition (enabling render-to-texture widgets)
        // punches holes in the backingstores using the alpha channel. Hence
        // the need for a true alpha format.
        if (QImage::toPixelFormat(format).alphaUsage() == QPixelFormat::UsesAlpha)
            m_alphaNeedsFill = true;
        else // upgrade but here we know app painting does not rely on alpha hence no need to fill
            format = qt_maybeAlphaVersionWithSameDepth(format);

        QWindowsNativeImage *oldwni = m_image.data();
        auto *newwni = new QWindowsNativeImage(size.width(), size.height(), format);

        if (oldwni && !region.isEmpty()) {
            const QImage &oldimg(oldwni->image());
            QImage &newimg(newwni->image());
            QRegion staticRegion(region);
            staticRegion &= QRect(0, 0, oldimg.width(), oldimg.height());
            staticRegion &= QRect(0, 0, newimg.width(), newimg.height());
            QPainter painter(&newimg);
            painter.setCompositionMode(QPainter::CompositionMode_Source);
            for (const QRect &rect : staticRegion)
                painter.drawImage(rect, oldimg, rect);
        }

        m_image.reset(newwni);
    }
}

Q_GUI_EXPORT void qt_scrollRectInImage(QImage &img, const QRect &rect, const QPoint &offset);

bool QWindowsBackingStore::scroll(const QRegion &area, int dx, int dy)
{
    if (m_image.isNull() || m_image->image().isNull())
        return false;

    const QPoint offset(dx, dy);
    for (const QRect &rect : area)
        qt_scrollRectInImage(m_image->image(), rect, offset);

    return true;
}

void QWindowsBackingStore::beginPaint(const QRegion &region)
{
    if (QWindowsContext::verbose > 1)
        qCDebug(lcQpaBackingStore) <<__FUNCTION__ << region;

    if (m_alphaNeedsFill) {
        QPainter p(&m_image->image());
        p.setCompositionMode(QPainter::CompositionMode_Source);
        const QColor blank = Qt::transparent;
        for (const QRect &r : region)
            p.fillRect(r, blank);
    }
}

HDC QWindowsBackingStore::getDC() const
{
    if (!m_image.isNull())
        return m_image->hdc();
    return nullptr;
}

QImage QWindowsBackingStore::toImage() const
{
    if (m_image.isNull()) {
        qCWarning(lcQpaBackingStore) <<__FUNCTION__ << "Image is null.";
        return QImage();
    }
    return m_image.data()->image();
}

QT_END_NAMESPACE