gfx/thebes/gfxRect.cpp

   1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
   2  * This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "gfxRect.h"
   7
   8 #include "nsMathUtils.h"
   9
  10 static bool
  11 WithinEpsilonOfInteger(gfxFloat aX, gfxFloat aEpsilon)
  12 {
  13     return fabs(NS_round(aX) - aX) <= fabs(aEpsilon);
  14 }
  15
  16 bool
  17 gfxRect::WithinEpsilonOfIntegerPixels(gfxFloat aEpsilon) const
  18 {
  19     NS_ASSERTION(-0.5 < aEpsilon && aEpsilon < 0.5, "Nonsense epsilon value");
  20     return (WithinEpsilonOfInteger(x, aEpsilon) &&
  21             WithinEpsilonOfInteger(y, aEpsilon) &&
  22             WithinEpsilonOfInteger(width, aEpsilon) &&
  23             WithinEpsilonOfInteger(height, aEpsilon));
  24 }
  25
  26 /* Clamp r to CAIRO_COORD_MIN .. CAIRO_COORD_MAX
  27  * these are to be device coordinates.
  28  *
  29  * Cairo is currently using 24.8 fixed point,
  30  * so -2^24 .. 2^24-1 is our valid
  31  */
  32
  33 #define CAIRO_COORD_MAX (16777215.0)
  34 #define CAIRO_COORD_MIN (-16777216.0)
  35
  36 void
  37 gfxRect::Condition()
  38 {
  39     // if either x or y is way out of bounds;
  40     // note that we don't handle negative w/h here
  41     if (x > CAIRO_COORD_MAX) {
  42         x = CAIRO_COORD_MAX;
  43         width = 0.0;
  44     }
  45
  46     if (y > CAIRO_COORD_MAX) {
  47         y = CAIRO_COORD_MAX;
  48         height = 0.0;
  49     }
  50
  51     if (x < CAIRO_COORD_MIN) {
  52         width += x - CAIRO_COORD_MIN;
  53         if (width < 0.0)
  54             width = 0.0;
  55         x = CAIRO_COORD_MIN;
  56     }
  57
  58     if (y < CAIRO_COORD_MIN) {
  59         height += y - CAIRO_COORD_MIN;
  60         if (height < 0.0)
  61             height = 0.0;
  62         y = CAIRO_COORD_MIN;
  63     }
  64
  65     if (x + width > CAIRO_COORD_MAX) {
  66         width = CAIRO_COORD_MAX - x;
  67     }
  68
  69     if (y + height > CAIRO_COORD_MAX) {
  70         height = CAIRO_COORD_MAX - y;
  71     }
  72 }
  73