plugin: add image analyser

1 files changed, 223 insertions, 0 deletions

diff --git a/plugin/src/Caelestia/imageanalyser.cpp b/plugin/src/Caelestia/imageanalyser.cpp
new file mode 100644
index 0000000..31fe839
--- /dev/null
+++ b/plugin/src/Caelestia/imageanalyser.cpp
@@ -0,0 +1,223 @@
+#include "imageanalyser.hpp"
+
+#include <QtConcurrent/qtconcurrentrun.h>
+#include <QtQuick/qquickitemgrabresult.h>
+#include <qfuturewatcher.h>
+#include <qimage.h>
+#include <qquickwindow.h>
+
+namespace caelestia {
+
+ImageAnalyser::ImageAnalyser(QObject* parent)
+    : QObject(parent)
+    , m_futureWatcher(new QFutureWatcher<AnalyseResult>(this))
+    , m_source("")
+    , m_sourceItem(nullptr)
+    , m_rescaleSize(128)
+    , m_dominantColour(0, 0, 0)
+    , m_luminance(0) {
+    QObject::connect(m_futureWatcher, &QFutureWatcher<AnalyseResult>::finished, this, [this]() {
+        if (!m_futureWatcher->future().isResultReadyAt(0)) {
+            return;
+        }
+
+        const auto result = m_futureWatcher->result();
+        if (m_dominantColour != result.first) {
+            m_dominantColour = result.first;
+            emit dominantColourChanged();
+        }
+        if (qFuzzyCompare(m_luminance + 1.0, result.second + 1.0)) {
+            m_luminance = result.second;
+            emit luminanceChanged();
+        }
+    });
+}
+
+QString ImageAnalyser::source() const {
+    return m_source;
+}
+
+void ImageAnalyser::setSource(const QString& source) {
+    if (m_source == source) {
+        return;
+    }
+
+    m_source = source;
+    emit sourceChanged();
+
+    if (m_sourceItem) {
+        m_sourceItem = nullptr;
+        emit sourceItemChanged();
+    }
+
+    requestUpdate();
+}
+
+QQuickItem* ImageAnalyser::sourceItem() const {
+    return m_sourceItem;
+}
+
+void ImageAnalyser::setSourceItem(QQuickItem* sourceItem) {
+    if (m_sourceItem == sourceItem) {
+        return;
+    }
+
+    m_sourceItem = sourceItem;
+    emit sourceItemChanged();
+
+    if (!m_source.isEmpty()) {
+        m_source = "";
+        emit sourceChanged();
+    }
+
+    requestUpdate();
+}
+
+int ImageAnalyser::rescaleSize() const {
+    return m_rescaleSize;
+}
+
+void ImageAnalyser::setRescaleSize(int rescaleSize) {
+    if (m_rescaleSize == rescaleSize) {
+        return;
+    }
+
+    m_rescaleSize = rescaleSize;
+    emit rescaleSizeChanged();
+
+    requestUpdate();
+}
+
+QColor ImageAnalyser::dominantColour() const {
+    return m_dominantColour;
+}
+
+qreal ImageAnalyser::luminance() const {
+    return m_luminance;
+}
+
+void ImageAnalyser::requestUpdate() {
+    if (m_source.isEmpty() && !m_sourceItem) {
+        return;
+    }
+
+    if (!m_sourceItem || (m_sourceItem->window() && m_sourceItem->window()->isVisible() && m_sourceItem->width() > 0 &&
+                             m_sourceItem->height() > 0)) {
+        update();
+    } else if (m_sourceItem) {
+        if (!m_sourceItem->window()) {
+            QObject::connect(m_sourceItem, &QQuickItem::windowChanged, this, &ImageAnalyser::requestUpdate,
+                Qt::SingleShotConnection);
+        } else if (!m_sourceItem->window()->isVisible()) {
+            QObject::connect(m_sourceItem->window(), &QQuickWindow::visibleChanged, this, &ImageAnalyser::requestUpdate,
+                Qt::SingleShotConnection);
+        }
+        if (m_sourceItem->width() <= 0) {
+            QObject::connect(
+                m_sourceItem, &QQuickItem::widthChanged, this, &ImageAnalyser::requestUpdate, Qt::SingleShotConnection);
+        }
+        if (m_sourceItem->height() <= 0) {
+            QObject::connect(m_sourceItem, &QQuickItem::heightChanged, this, &ImageAnalyser::requestUpdate,
+                Qt::SingleShotConnection);
+        }
+    }
+}
+
+void ImageAnalyser::update() {
+    if (m_source.isEmpty() && !m_sourceItem) {
+        return;
+    }
+
+    if (m_futureWatcher->isRunning()) {
+        m_futureWatcher->cancel();
+    }
+
+    if (m_sourceItem) {
+        const QSharedPointer<const QQuickItemGrabResult> grabResult = m_sourceItem->grabToImage();
+        QObject::connect(grabResult.data(), &QQuickItemGrabResult::ready, this, [grabResult, this]() {
+            m_futureWatcher->setFuture(QtConcurrent::run(&ImageAnalyser::analyse, grabResult->image(), m_rescaleSize));
+        });
+    } else {
+        m_futureWatcher->setFuture(QtConcurrent::run([=, this](QPromise<AnalyseResult>& promise) {
+            const QImage image(m_source);
+            analyse(promise, image, m_rescaleSize);
+        }));
+    }
+}
+
+void ImageAnalyser::analyse(QPromise<AnalyseResult>& promise, const QImage& image, int rescaleSize) {
+    if (image.isNull()) {
+        qWarning() << "ImageAnalyser::analyse: image is null";
+        return;
+    }
+
+    QImage img = image;
+
+    if (rescaleSize > 0 && (img.width() > rescaleSize || img.height() > rescaleSize)) {
+        img = img.scaled(rescaleSize, rescaleSize, Qt::KeepAspectRatio, Qt::FastTransformation);
+    }
+
+    if (promise.isCanceled()) {
+        return;
+    }
+
+    if (img.format() != QImage::Format_ARGB32) {
+        img = img.convertToFormat(QImage::Format_ARGB32);
+    }
+
+    if (promise.isCanceled()) {
+        return;
+    }
+
+    const uchar* data = img.bits();
+    const int width = img.width();
+    const int height = img.height();
+    const qsizetype bytesPerLine = img.bytesPerLine();
+
+    std::unordered_map<quint32, int> colours;
+    qreal totalLuminance = 0.0;
+    int count = 0;
+
+    for (int y = 0; y < height; ++y) {
+        const uchar* line = data + y * bytesPerLine;
+        for (int x = 0; x < width; ++x) {
+            if (promise.isCanceled()) {
+                return;
+            }
+
+            const uchar* pixel = line + x * 4;
+
+            if (pixel[3] == 0) {
+                continue;
+            }
+
+            const quint32 mr = static_cast<quint32>(pixel[0] & 0xF8);
+            const quint32 mg = static_cast<quint32>(pixel[1] & 0xF8);
+            const quint32 mb = static_cast<quint32>(pixel[2] & 0xF8);
+            ++colours[(mr << 16) | (mg << 8) | mb];
+
+            const qreal r = pixel[0] / 255.0;
+            const qreal g = pixel[1] / 255.0;
+            const qreal b = pixel[2] / 255.0;
+            totalLuminance += std::sqrt(0.299 * r * r + 0.587 * g * g + 0.114 * b * b);
+            ++count;
+        }
+    }
+
+    quint32 dominantColour = 0;
+    int maxCount = 0;
+    for (const auto& [colour, colourCount] : colours) {
+        if (promise.isCanceled()) {
+            return;
+        }
+
+        if (colourCount > maxCount) {
+            dominantColour = colour;
+            maxCount = colourCount;
+        }
+    }
+
+    promise.addResult(qMakePair(QColor((0xFFu << 24) | dominantColour), count == 0 ? 0.0 : totalLuminance / count));
+}
+
+} // namespace caelestia