QGLEllipseMaskGenerator Class Reference

Inheritance diagram for QGLEllipseMaskGenerator:

Public Functions
void	drawMask (const QRect &rect)
	QGLEllipseMaskGenerator (const QRectF &rect, const QTransform &matrix, QGLOffscreen &offscreen, GLuint maskFragmentProgram, int *maskVariableLocations)
QRect	screenRect ()
Public Functions inherited from QGLMaskGenerator
QTransform	matrix () const
QPainterPath	path () const
	QGLMaskGenerator (const QPainterPath &path, const QTransform &matrix, qreal stroke_width=-1)
qreal	strokeWidth () const
virtual	~QGLMaskGenerator ()

Properties
QRectF	ellipseRect
GLuint	maskFragmentProgram
int *	maskVariableLocations
QGLOffscreen *	offscreen
QRect	screen_rect
float	vertexArray [4 *2]

Detailed Description

Definition at line 3088 of file qpaintengine_opengl.cpp.

Constructors and Destructors

QGLEllipseMaskGenerator()

QGLEllipseMaskGenerator::QGLEllipseMaskGenerator	(	const QRectF &	rect,
		const QTransform &	matrix,
		QGLOffscreen &	offscreen,
		GLuint	maskFragmentProgram,
		int *	maskVariableLocations
	)

Definition at line 3287 of file qpaintengine_opengl.cpp.

    : QGLMaskGenerator(ellipseRectToPath(rect), matrix),
      ellipseRect(rect),
      offscreen(&offs),
      maskFragmentProgram(program),
      maskVariableLocations(locations)
{
}

Functions

drawMask()

void QGLEllipseMaskGenerator::drawMask ( const QRect &  rect )

virtual

Implements QGLMaskGenerator.

Definition at line 3338 of file qpaintengine_opengl.cpp.

{
#ifdef QT_OPENGL_ES
    Q_UNUSED(rect);
#else
    QGLContext *ctx = offscreen->context();
    offscreen->bind();

    glDisable(GL_TEXTURE_GEN_S);
    glDisable(GL_TEXTURE_1D);

    // fragment program needs the inverse radii of the ellipse
    glTexCoord2f(1.0f / (ellipseRect.width() * 0.5f),
                 1.0f / (ellipseRect.height() * 0.5f));

    QTransform translate(1, 0, 0, 1, -ellipseRect.center().x(), -ellipseRect.center().y());
    QTransform gl_to_qt(1, 0, 0, -1, 0, offscreen->drawableSize().height());
    QTransform inv_matrix = gl_to_qt * matrix().inverted() * translate;

    float m[3][4] = { { float(inv_matrix.m11()), float(inv_matrix.m12()), float(inv_matrix.m13()) },
                      { float(inv_matrix.m21()), float(inv_matrix.m22()), float(inv_matrix.m23()) },
                      { float(inv_matrix.m31()), float(inv_matrix.m32()), float(inv_matrix.m33()) } };

    QPoint offs(screen_rect.left() - rect.left(), (offscreen->drawableSize().height() - screen_rect.top())
                                                - (offscreen->offscreenSize().height() - rect.top()));

    // last component needs to be 1.0f to avoid Nvidia bug on linux
    float ellipse_offset[4] = { float(offs.x()), float(offs.y()), 0.0f, 1.0f };

    GLfloat vertexArray[4 * 2];
    qt_add_rect_to_array(rect, vertexArray);

    glBlendFunc(GL_ONE, GL_ZERO); // set mask
    glEnable(GL_FRAGMENT_PROGRAM_ARB);
    glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, maskFragmentProgram);

    glProgramLocalParameter4fvARB(GL_FRAGMENT_PROGRAM_ARB, maskVariableLocations[VAR_INV_MATRIX_M0], m[0]);
    glProgramLocalParameter4fvARB(GL_FRAGMENT_PROGRAM_ARB, maskVariableLocations[VAR_INV_MATRIX_M1], m[1]);
    glProgramLocalParameter4fvARB(GL_FRAGMENT_PROGRAM_ARB, maskVariableLocations[VAR_INV_MATRIX_M2], m[2]);

    glProgramLocalParameter4fvARB(GL_FRAGMENT_PROGRAM_ARB, maskVariableLocations[VAR_ELLIPSE_OFFSET], ellipse_offset);

    glEnableClientState(GL_VERTEX_ARRAY);
    glVertexPointer(2, GL_FLOAT, 0, vertexArray);
    glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
    glDisableClientState(GL_VERTEX_ARRAY);
    glDisable(GL_FRAGMENT_PROGRAM_ARB);
#endif
}

screenRect()

QRect QGLEllipseMaskGenerator::screenRect ( )

virtual

Implements QGLMaskGenerator.

Definition at line 3296 of file qpaintengine_opengl.cpp.

{
    QPointF center = ellipseRect.center();

    QPointF points[] = {
        QPointF(ellipseRect.left(), center.y()),
        QPointF(ellipseRect.right(), center.y()),
        QPointF(center.x(), ellipseRect.top()),
        QPointF(center.x(), ellipseRect.bottom())
    };

    qreal min_screen_delta_len = QREAL_MAX;

    for (int i = 0; i < 4; ++i) {
        QPointF delta = points[i] - center;

        // normalize
        delta /= qSqrt(delta.x() * delta.x() + delta.y() * delta.y());

        QPointF screen_delta(matrix().m11() * delta.x() + matrix().m21() * delta.y(),
                             matrix().m12() * delta.x() + matrix().m22() * delta.y());

        min_screen_delta_len = qMin(min_screen_delta_len,
                                    qreal(qSqrt(screen_delta.x() * screen_delta.x() + screen_delta.y() * screen_delta.y())));
    }

    const qreal padding = 2.0f;

    qreal grow = padding / min_screen_delta_len;

    QRectF boundingRect = ellipseRect.adjusted(-grow, -grow, grow, grow);

    boundingRect = matrix().mapRect(boundingRect);

    QPointF p(0.5, 0.5);

    screen_rect = QRect((boundingRect.topLeft() - p).toPoint(),
                        (boundingRect.bottomRight() + p).toPoint());

    return screen_rect;
}

Properties

ellipseRect

QRectF QGLEllipseMaskGenerator::ellipseRect

private

Definition at line 3099 of file qpaintengine_opengl.cpp.

Referenced by drawMask(), and screenRect().

maskFragmentProgram

GLuint QGLEllipseMaskGenerator::maskFragmentProgram

private

Definition at line 3103 of file qpaintengine_opengl.cpp.

Referenced by drawMask().

maskVariableLocations

int* QGLEllipseMaskGenerator::maskVariableLocations

private

Definition at line 3105 of file qpaintengine_opengl.cpp.

Referenced by drawMask().

offscreen

QGLOffscreen* QGLEllipseMaskGenerator::offscreen

private

Definition at line 3101 of file qpaintengine_opengl.cpp.

screen_rect

QRect QGLEllipseMaskGenerator::screen_rect

private

Definition at line 3097 of file qpaintengine_opengl.cpp.

Referenced by QOpenGLPaintEnginePrivate::copyDrawable(), drawMask(), and screenRect().

vertexArray

float QGLEllipseMaskGenerator::vertexArray[4 *2]

private

Definition at line 3107 of file qpaintengine_opengl.cpp.

Referenced by QOpenGLPaintEnginePrivate::composite(), QOpenGLPaintEnginePrivate::drawFastRect(), QOpenGLPaintEngine::drawLines(), drawMask(), QOpenGLPaintEngine::drawPoints(), QOpenGLPaintEngine::drawPolygon(), QOpenGLPaintEngine::drawStaticTextItem(), QOpenGLPaintEngine::drawTextureRect(), and QOpenGLPaintEngine::drawTiledPixmap().

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The documentation for this class was generated from the following file:

• /src/opengl/qpaintengine_opengl.cpp