QtAV/examples/filters/SimpleFilter.cpp

/******************************************************************************
    QtAV:  Multimedia framework based on Qt and FFmpeg
    Copyright (C) 2012-2022 Wang Bin <wbsecg1@gmail.com>

*   This file is part of QtAV (from 2013)

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
******************************************************************************/

#include "SimpleFilter.h"
#include <QWidget>
#include <math.h>
#include <QTime>
namespace QtAV {

SimpleFilter::SimpleFilter(QObject *parent):
    VideoFilter(parent)
  , mCanRot(true)
  , mWave(true)
{
    srand(QTime::currentTime().msec());
    mStartValue = (qreal)(rand()%1000)/qreal(1000.0);
    mTime.start();
    startTimer(100);
}

SimpleFilter::~SimpleFilter()
{
}

void SimpleFilter::enableRotate(bool r)
{
    mCanRot = r;
}

void SimpleFilter::enableWaveEffect(bool w)
{
    mWave = w;
}

void SimpleFilter::setText(const QString &text)
{
    mText = text;
}

QString SimpleFilter::text() const
{
    return mText;
}

void SimpleFilter::setImage(const QImage &img)
{
    mImage = img;
}

void SimpleFilter::prepare()
{
    VideoFilterContext *ctx = static_cast<VideoFilterContext*>(context());
    if (!mText.isEmpty()) {
        ctx->font.setPixelSize(32);
        ctx->font.setBold(true);
        if (!mCanRot)
            return;
        mMat.translate(ctx->rect.center().x(), 0, 0);
    } else if (!mImage.isNull()) {
        if (!mCanRot)
            return;
        mMat.translate(ctx->rect.x() + mImage.width()/2, 0, 0);
    }
    if (mCanRot) {
        mMat.rotate(mStartValue*360, 0, 1, -0.1);
    }
}

void SimpleFilter::timerEvent(QTimerEvent *)
{
    if (qobject_cast<QWidget*>(parent()))
        ((QWidget*)parent())->update();
}

void SimpleFilter::process(Statistics *statistics, VideoFrame *frame)
{
    Q_UNUSED(statistics);
    Q_UNUSED(frame);
    if (!isEnabled())
        return;
    int t = mTime.elapsed()/100;
    VideoFilterContext *ctx = static_cast<VideoFilterContext*>(context());
    if (mCanRot) {
        mMat.rotate(2, 0, 1, -0.1);
        ctx->transform = mMat.toTransform();
    }
    if (mText.isEmpty()) {
        if (mImage.isNull())
            return;
        if (mCanRot)
            ctx->drawImage(QPointF(-mImage.width()/2, ctx->rect.y()), mImage, QRectF(0, 0, mImage.width(), mImage.height()));
        else
            ctx->drawImage(ctx->rect.topLeft(), mImage, QRectF(0, 0, mImage.width(), mImage.height()));
        return;
    }
    if (mWave) {
        static int sin_tbl[16] = {
             0, 38, 71, 92, 100, 92, 71, 38, 0, -38, -71, -92, -100, -92, -71, -38
        };

        QFontMetrics fm(ctx->font);
        int h = fm.height();
        int x = ctx->rect.x();
        int y = ctx->rect.y() + h + fm.descent();
        for (int i = 0; i < mText.size(); ++i) {
            int i16 = (t+i) & 15;
            ctx->pen.setColor(QColor::fromHsv((15-i16)*16, 255, 255));
            if (mCanRot)
                ctx->drawPlainText(QPointF(x-fm.boundingRect(mText).width()/2-ctx->rect.x(), y-sin_tbl[i16]*h/400), mText.mid(i, 1));
            else
                ctx->drawPlainText(QPointF(x, y-sin_tbl[i16]*h/400), mText.mid(i, 1));
            x += fm.boundingRect(mText[i]).width();
        }
    } else {
        qreal c = fabs(sin((float)t));
        c += mStartValue;
        c /= 2.0;
        QLinearGradient g(0, 0, 100, 32);
        g.setSpread(QGradient::ReflectSpread);
        g.setColorAt(0, QColor::fromHsvF(c, 1, 1, 1));
        g.setColorAt(1, QColor::fromHsvF(c > 0.5?c-0.5:c+0.5, 1, 1, 1));
        ctx->pen.setBrush(QBrush(g));
        ctx->drawRichText(ctx->rect, mText);
return;
        if (mCanRot) {
            QFontMetrics fm(ctx->font);
            ctx->drawPlainText(QRectF(-fm.boundingRect(mText).width()/2, ctx->rect.y(), ctx->rect.width(), ctx->rect.height()), Qt::TextWordWrap, mText);
        } else {
            ctx->drawPlainText(ctx->rect, Qt::TextWordWrap, mText);
        }
    }
}

} //namespace QtAV