1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #include "printing/units.h"
7 #include "base/logging.h"
8 #include "printing/print_job_constants.h"
12 int ConvertUnit(double value, int old_unit, int new_unit) {
13 DCHECK_GT(new_unit, 0);
14 DCHECK_GT(old_unit, 0);
15 // With integer arithmetic, to divide a value with correct rounding, you need
16 // to add half of the divisor value to the dividend value. You need to do the
17 // reverse with negative number.
19 return ((value * new_unit) + (old_unit / 2)) / old_unit;
21 return ((value * new_unit) - (old_unit / 2)) / old_unit;
25 double ConvertUnitDouble(double value, double old_unit, double new_unit) {
26 DCHECK_GT(new_unit, 0);
27 DCHECK_GT(old_unit, 0);
28 return value * new_unit / old_unit;
31 int ConvertPixelsToPoint(int pixels) {
32 return ConvertUnit(pixels, kPixelsPerInch, kPointsPerInch);
35 double ConvertPixelsToPointDouble(double pixels) {
36 return ConvertUnitDouble(pixels, kPixelsPerInch, kPointsPerInch);
39 double ConvertPointsToPixelDouble(double points) {
40 return ConvertUnitDouble(points, kPointsPerInch, kPixelsPerInch);
43 } // namespace printing