Kaydet (Commit) 6064e4f3 authored tarafından Chris Sherlock's avatar Chris Sherlock Kaydeden (comit) Noel Grandin

tools: document and test sanitiseMm100ToTwip()

Change-Id: I2f6349c679a714e5168ae3c5eccd054c5522bbc9
Reviewed-on: https://gerrit.libreoffice.org/53814Tested-by: 's avatarJenkins <ci@libreoffice.org>
Reviewed-by: 's avatarNoel Grandin <noel.grandin@collabora.co.uk>
üst 6b2fa779
......@@ -55,7 +55,19 @@ inline long FRound( double fVal )
return fVal > 0.0 ? static_cast<long>( fVal + 0.5 ) : -static_cast<long>( -fVal + 0.5 );
}
// return (n >= 0)? (n*72+63)/127: (n*72-63)/127;
/** Convert 100th-mm to twips
A twip is 1/20 of a point, one inch is equal to 72 points, and
one inch is 2,540 100th-mm.
Thus:
twips = n * 72 / 2,540 / 20
= n * 72 / 127
Adding 63 (half of 127) fixes truncation issues in int arithmetic.
This formula is (n>=0) ? (n*72+63) / 127 : (n*72-63) / 127
*/
inline sal_Int64 sanitiseMm100ToTwip(sal_Int64 n)
{
if (n >= 0)
......@@ -68,7 +80,7 @@ inline sal_Int64 sanitiseMm100ToTwip(sal_Int64 n)
if (o3tl::checked_multiply<sal_Int64>(n, 72, n) || o3tl::checked_sub<sal_Int64>(n, 63, n))
n = SAL_MIN_INT64;
}
return n / 127;
return n / 127; // 127 is 2,540 100th-mm divided by 20pts
}
#endif
......
......@@ -25,6 +25,7 @@ $(eval $(call gb_CppunitTest_add_exception_objects,tools_test, \
tools/qa/cppunit/test_color \
tools/qa/cppunit/test_rectangle \
tools/qa/cppunit/test_minmax \
tools/qa/cppunit/test_100mm2twips \
))
$(eval $(call gb_CppunitTest_use_sdk_api,tools_test))
......
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* 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/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
*/
#include <sal/types.h>
#include <sal/log.hxx>
#include <cppunit/TestFixture.h>
#include <cppunit/extensions/HelperMacros.h>
#include <cppunit/plugin/TestPlugIn.h>
#include <tools/helpers.hxx>
#include <cassert>
namespace tools
{
class cm2TwipsTest : public CppUnit::TestFixture
{
public:
void testConvert()
{
sal_Int32 nActual = sanitiseMm100ToTwip(255);
sal_Int32 nExpected = 145;
CPPUNIT_ASSERT_EQUAL(nExpected, nActual);
nActual = sanitiseMm100ToTwip(-255);
nExpected = -145;
CPPUNIT_ASSERT_EQUAL(nExpected, nActual);
}
CPPUNIT_TEST_SUITE(cm2TwipsTest);
CPPUNIT_TEST(testConvert);
CPPUNIT_TEST_SUITE_END();
};
CPPUNIT_TEST_SUITE_REGISTRATION(cm2TwipsTest);
} // namespace tools
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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