okular/core/utils.cpp

/*
    SPDX-FileCopyrightText: 2006 Luigi Toscano <luigi.toscano@tiscali.it>
    SPDX-FileCopyrightText: 2008 Pino Toscano <pino@kde.org>

    SPDX-License-Identifier: GPL-2.0-or-later
*/

#include "utils.h"
#include "utils_p.h"

#include "debug_p.h"
#include "settings_core.h"

#include <QApplication>
#include <QIODevice>
#include <QImage>
#include <QRect>
#include <QScreen>
#include <QWidget>
#include <QWindow>

using namespace Okular;

QRect Utils::rotateRect(const QRect source, int width, int height, int orientation)
{
    QRect ret;

    // adapt the coordinates of the boxes to the rotation
    switch (orientation) {
    case 1:
        ret = QRect(width - source.y() - source.height(), source.x(), source.height(), source.width());
        break;
    case 2:
        ret = QRect(width - source.x() - source.width(), height - source.y() - source.height(), source.width(), source.height());
        break;
    case 3:
        ret = QRect(source.y(), height - source.x() - source.width(), source.height(), source.width());
        break;
    case 0:  // no modifications
    default: // other cases
        ret = source;
    }

    return ret;
}

QSizeF Utils::realDpi(const QWindow *windowOnScreen)
{
    const QScreen *screen = windowOnScreen ? windowOnScreen->screen() : qGuiApp->primaryScreen();

    if (screen) {
        const QSizeF res(screen->physicalDotsPerInchX(), screen->physicalDotsPerInchY());
        if (res.width() > 0 && res.height() > 0) {
            if (qAbs(res.width() - res.height()) / qMin(res.height(), res.width()) < 0.15) {
                return res;
            } else {
                qCDebug(OkularCoreDebug) << "QScreen calculation returned a non square dpi." << res << ". Falling back";
            }
        }
    }
    return QSizeF(72, 72);
}

inline static bool isPaperColor(QRgb argb, QRgb paperColor)
{
    return (argb & 0xFFFFFF) == (paperColor & 0xFFFFFF); // ignore alpha
}

NormalizedRect Utils::imageBoundingBox(const QImage *image)
{
    if (!image) {
        return NormalizedRect();
    }

    const int width = image->width();
    const int height = image->height();
    const QRgb paperColor = SettingsCore::paperColor().rgb();
    int left, top, bottom, right, x, y;

#ifdef BBOX_DEBUG
    QTime time;
    time.start();
#endif

    // Scan pixels for top non-white
    for (top = 0; top < height; ++top) {
        for (x = 0; x < width; ++x) {
            if (!isPaperColor(image->pixel(x, top), paperColor)) {
                goto got_top;
            }
        }
    }
    return NormalizedRect(0, 0, 0, 0); // the image is blank
got_top:
    left = right = x;

    // Scan pixels for bottom non-white
    for (bottom = height - 1; bottom >= top; --bottom) {
        for (x = width - 1; x >= 0; --x) {
            if (!isPaperColor(image->pixel(x, bottom), paperColor)) {
                goto got_bottom;
            }
        }
    }
    Q_ASSERT(0); // image changed?!
got_bottom:
    if (x < left) {
        left = x;
    }
    if (x > right) {
        right = x;
    }

    // Scan for leftmost and rightmost (we already found some bounds on these):
    for (y = top; y <= bottom && (left > 0 || right < width - 1); ++y) {
        for (x = 0; x < left; ++x) {
            if (!isPaperColor(image->pixel(x, y), paperColor)) {
                left = x;
            }
        }
        for (x = width - 1; x > right + 1; --x) {
            if (!isPaperColor(image->pixel(x, y), paperColor)) {
                right = x;
            }
        }
    }

    NormalizedRect bbox(QRect(left, top, (right - left + 1), (bottom - top + 1)), image->width(), image->height());

#ifdef BBOX_DEBUG
    qCDebug(OkularCoreDebug) << "Computed bounding box" << bbox << "in" << time.elapsed() << "ms";
#endif

    return bbox;
}

void Okular::copyQIODevice(QIODevice *from, QIODevice *to)
{
    QByteArray buffer(65536, '\0');
    qint64 read = 0;
    while ((read = from->read(buffer.data(), buffer.size())) > 0) {
        qint64 written = to->write(buffer.constData(), read);
        if (read != written) {
            break;
        }
    }
}

QTransform Okular::buildRotationMatrix(Rotation rotation)
{
    QTransform matrix;
    matrix.rotate((int)rotation * 90);

    switch (rotation) {
    case Rotation90:
        matrix.translate(0, -1);
        break;
    case Rotation180:
        matrix.translate(-1, -1);
        break;
    case Rotation270:
        matrix.translate(-1, 0);
        break;
    default:;
    }

    return matrix;
}

/* kate: replace-tabs on; indent-width 4; */