path: root/src/declarative/fx/qfxblendedimage.cpp

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#include "qfxblendedimage.h"
#include <QtDeclarative/qmlcontext.h>

#if defined(QFX_RENDER_OPENGL2)
#include <glbasicshaders.h>
#endif

QT_BEGIN_NAMESPACE

/*!
    \qmlclass BlendedImage
    \brief The BlendedImage elements blends two different images depending on a blend ratio.

    This element can be used to simulate blur on slow devices by setting secondaryUrl with
    a pre-rendered blurred version of primaryUrl.

    Note that this class will only work under OpenGL. On the software canvas it will display
    only the primary image unless the blend is > 0.75, in which case it will display only the
    secondary image.
*/

/*!
    \internal
    \class QFxBlendedImage
    \brief The QFxBlendedImage blends two different images depending on a blend ratio.

    This class can be used to simulate blur on slow devices by setting secondaryUrl with
    a pre-rendered blurred version of primaryUrl.

    Note that this class will only work under OpenGL. On the software canvas it will display
    only the primary image unless the blend is > 0.75, in which case it will display only the
    secondary image.
*/
QFxBlendedImage::QFxBlendedImage(QFxItem *parent)
: QFxItem(parent), _blend(0), _smooth(false), dirty(false)
{
#if defined(QFX_RENDER_OPENGL2)
    setOptions(HasContents);
#endif
}

/*!
    \qmlproperty string BlendedImage::primaryUrl
    The URL of the first image to be displayed in this item.
*/
QString QFxBlendedImage::primaryUrl() const
{
    return primSrc;
}

void QFxBlendedImage::primaryLoaded()
{
    primPix = QFxPixmap(primUrl);
    dirty = true;
    update();
}

void QFxBlendedImage::setPrimaryUrl(const QString &url)
{
    if (primSrc == url)
        return;
    if (!primSrc.isEmpty())
        QFxPixmap::cancelGet(primUrl,this,SLOT(primaryLoaded()));
    primSrc = url;
    primUrl = qmlContext(this)->resolvedUrl(url);
    if (!primSrc.isEmpty())
        QFxPixmap::get(qmlEngine(this), primUrl,this,SLOT(primaryLoaded()));
}

/*!
    \qmlproperty string BlendedImage::secondaryUrl
    The URL of the second image to be displayed in this item.
*/
QString QFxBlendedImage::secondaryUrl() const
{
    return secSrc;
}

void QFxBlendedImage::secondaryLoaded()
{
    secPix = QFxPixmap(secUrl);
    dirty = true;
    update();
}

void QFxBlendedImage::setSecondaryUrl(const QString &url)
{
    if (secSrc == url)
        return;
    if (!secSrc.isEmpty())
        QFxPixmap::cancelGet(secUrl,this,SLOT(secondaryLoaded()));
    secSrc = url;
    secUrl = qmlContext(this)->resolvedUrl(url);
    if (!secSrc.isEmpty())
        QFxPixmap::get(qmlEngine(this), secUrl,this,SLOT(secondaryLoaded()));
}

/*!
    \qmlproperty real BlendedImage::blend
    The ratio used to blend the two images.

    If blend has a value of 0, only the first image will be displayed.
    If blend has a value of 1, only the second image will be displayed.
*/
qreal QFxBlendedImage::blend() const
{
    return _blend;
}

void QFxBlendedImage::setBlend(qreal b)
{
    _blend = b;
    update();
}

/*!
    \qmlproperty bool BlendedImage::smooth

    Set this property if you want the image to be smoothly filtered when scaled or
    transformed.  Smooth filtering gives better visual quality, but is slower.  If
    the BlendedImage is displayed at its natural size, this property has no visual or
    performance effect.

    \note Generally scaling artifacts are only visible if the image is stationary on
    the screen.  A common pattern when animating an image is to disable smooth
    filtering at the beginning of the animation and reenable it at the conclusion.
 */
bool QFxBlendedImage::smoothTransform() const
{
    return _smooth;
}

void QFxBlendedImage::setSmoothTransform(bool s)
{
    if (_smooth == s)
        return;
    _smooth = s;
    update();
}

#if defined(QFX_RENDER_QPAINTER) 

void QFxBlendedImage::paintContents(QPainter &p)
{
    if (primSrc.isNull() && secSrc.isNull())
        return;

    if (_smooth) {
        p.save();
        p.setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform, _smooth);
    }

    if (_blend < 0.75)
        p.drawImage(0, 0, primPix);
    else
        p.drawImage(0, 0, secPix);

    if (_smooth) {
        p.restore();
    }
}

#elif defined(QFX_RENDER_OPENGL2)

void QFxBlendedImage::paintGLContents(GLPainter &p)
{
    static DualTextureBlendShader *shader = 0;
    if (!shader)
        shader = new DualTextureBlendShader();

    if (dirty) {
        prim.clear();
        sec.clear();
        prim.setImage(primPix);
        sec.setImage(secPix);

        dirty = false;
    }

    if (prim.isNull() || sec.isNull()) {

        return;
    }

    GLfloat vertices[8];
    GLfloat texVertices[8];

    float widthV = width();
    float heightV = height();
    if (!widthV)
        widthV = qMax(primPix.width(), secPix.width());
    if (!heightV)
        heightV = qMax(primPix.height(), secPix.height());

    vertices[0] = 0; vertices[1] = heightV;
    vertices[2] = widthV; vertices[3] = heightV;
    vertices[4] = 0; vertices[5] = 0;
    vertices[6] = widthV; vertices[7] = 0;

    texVertices[0] = 0; texVertices[1] = 0;
    texVertices[2] = 1; texVertices[3] = 0;
    texVertices[4] = 0; texVertices[5] = 1;
    texVertices[6] = 1; texVertices[7] = 1;

    if (_blend == 0 || _blend == 1) {
        QGLShaderProgram *tshader = p.useTextureShader();

        GLTexture *tex = 0;

        if (_blend == 0)
            tex = &prim;
        else
            tex = &sec;

        tshader->setAttributeArray(SingleTextureShader::Vertices, vertices, 2);
        tshader->setAttributeArray(SingleTextureShader::TextureCoords, texVertices, 2);

        glBindTexture(GL_TEXTURE_2D, tex->texture());
        glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

        tshader->disableAttributeArray(SingleTextureShader::Vertices);
        tshader->disableAttributeArray(SingleTextureShader::TextureCoords);
    } else {

        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, prim.texture());
        glActiveTexture(GL_TEXTURE1);
        glBindTexture(GL_TEXTURE_2D, sec.texture());

        shader->enable();
        shader->setOpacity(1);
        qreal b = _blend;
        if (b > 1) b = 1;
        else if (b < 0) b = 0;
        shader->setBlend(b);
        shader->setTransform(p.activeTransform);

        shader->setAttributeArray(DualTextureBlendShader::Vertices, vertices, 2);
        shader->setAttributeArray(DualTextureBlendShader::TextureCoords, texVertices, 2);
        shader->setAttributeArray(DualTextureBlendShader::BlendTextureCoords, texVertices, 2);

        glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

        shader->disableAttributeArray(DualTextureBlendShader::Vertices);
        shader->disableAttributeArray(DualTextureBlendShader::TextureCoords);
        shader->disableAttributeArray(DualTextureBlendShader::BlendTextureCoords);

        glBindTexture(GL_TEXTURE_2D, 0);
        glActiveTexture(GL_TEXTURE0);
    }
}
#endif

QML_DEFINE_TYPE(QFxBlendedImage,BlendedImage);

QT_END_NAMESPACE