gecko-dev/gfx/thebes/gfxMatrix.cpp

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "gfxMatrix.h"
#include "cairo.h"

#define CAIRO_MATRIX(x) reinterpret_cast<cairo_matrix_t*>((x))
#define CONST_CAIRO_MATRIX(x) reinterpret_cast<const cairo_matrix_t*>((x))

const gfxMatrix&
gfxMatrix::Reset()
{
    cairo_matrix_init_identity(CAIRO_MATRIX(this));
    return *this;
}

const gfxMatrix&
gfxMatrix::Invert()
{
    cairo_matrix_invert(CAIRO_MATRIX(this));
    return *this;
}

const gfxMatrix&
gfxMatrix::Scale(gfxFloat x, gfxFloat y)
{
    cairo_matrix_scale(CAIRO_MATRIX(this), x, y);
    return *this;
}

const gfxMatrix&
gfxMatrix::Translate(const gfxPoint& pt)
{
    cairo_matrix_translate(CAIRO_MATRIX(this), pt.x, pt.y);
    return *this;
}

const gfxMatrix&
gfxMatrix::Rotate(gfxFloat radians)
{
    cairo_matrix_rotate(CAIRO_MATRIX(this), radians);
    return *this;
}

const gfxMatrix&
gfxMatrix::Multiply(const gfxMatrix& m)
{
    cairo_matrix_multiply(CAIRO_MATRIX(this), CAIRO_MATRIX(this), CONST_CAIRO_MATRIX(&m));
    return *this;
}

const gfxMatrix&
gfxMatrix::PreMultiply(const gfxMatrix& m)
{
    cairo_matrix_multiply(CAIRO_MATRIX(this), CONST_CAIRO_MATRIX(&m), CAIRO_MATRIX(this));
    return *this;
}

gfxPoint
gfxMatrix::Transform(const gfxPoint& point) const
{
    gfxPoint ret = point;
    cairo_matrix_transform_point(CONST_CAIRO_MATRIX(this), &ret.x, &ret.y);
    return ret;
}

gfxSize
gfxMatrix::Transform(const gfxSize& size) const
{
    gfxSize ret = size;
    cairo_matrix_transform_distance(CONST_CAIRO_MATRIX(this), &ret.width, &ret.height);
    return ret;
}

gfxRect
gfxMatrix::Transform(const gfxRect& rect) const
{
    return gfxRect(Transform(rect.TopLeft()), Transform(rect.Size()));
}

gfxRect
gfxMatrix::TransformBounds(const gfxRect& rect) const
{
    /* Code taken from cairo-matrix.c, _cairo_matrix_transform_bounding_box isn't public */
    int i;
    double quad_x[4], quad_y[4];
    double min_x, max_x;
    double min_y, max_y;

    quad_x[0] = rect.X();
    quad_y[0] = rect.Y();
    cairo_matrix_transform_point (CONST_CAIRO_MATRIX(this), &quad_x[0], &quad_y[0]);

    quad_x[1] = rect.XMost();
    quad_y[1] = rect.Y();
    cairo_matrix_transform_point (CONST_CAIRO_MATRIX(this), &quad_x[1], &quad_y[1]);

    quad_x[2] = rect.X();
    quad_y[2] = rect.YMost();
    cairo_matrix_transform_point (CONST_CAIRO_MATRIX(this), &quad_x[2], &quad_y[2]);

    quad_x[3] = rect.XMost();
    quad_y[3] = rect.YMost();
    cairo_matrix_transform_point (CONST_CAIRO_MATRIX(this), &quad_x[3], &quad_y[3]);

    min_x = max_x = quad_x[0];
    min_y = max_y = quad_y[0];

    for (i = 1; i < 4; i++) {
        if (quad_x[i] < min_x)
            min_x = quad_x[i];
        if (quad_x[i] > max_x)
            max_x = quad_x[i];

        if (quad_y[i] < min_y)
            min_y = quad_y[i];
        if (quad_y[i] > max_y)
            max_y = quad_y[i];
    }

    return gfxRect(min_x, min_y, max_x - min_x, max_y - min_y);
}


static void NudgeToInteger(double *aVal)
{
    float f = float(*aVal);
    float r = NS_roundf(f);
    if (f == r) {
        *aVal = r;
    }
}

void
gfxMatrix::NudgeToIntegers(void)
{
    NudgeToInteger(&xx);
    NudgeToInteger(&xy);
    NudgeToInteger(&yx);
    NudgeToInteger(&yy);
    NudgeToInteger(&x0);
    NudgeToInteger(&y0);
}