SkPDF: re-work SkPDFUtils::FloatToDecimal
* do a lot less floating-point math by converting to
an integer as early as possible [faster].
* round rather than truncate.
* use 8 significant digits rather than 9 when possible.
* remove trailing zeros in fractions.
before:
0.12 ! PDFScalar nonrendering
after:
0.07 ! PDFScalar nonrendering
Accuracy guaranteed by existing unit test.
Example diffs:
-/Shading <</Function <</C0 [.321568638 .333333343 .321568638]
+/Shading <</Function <</C0 [.32156864 .33333334 .32156864]
-/C1 [.258823543 .270588248 .258823543]
+/C1 [.25882354 .27058825 .25882354]
-1 0 0 -1 20 120.394500 Tm
+1 0 0 -1 20 120.394501 Tm
-1 0 0 -1 20 184.789001 Tm
+1 0 0 -1 20 184.789 Tm
-291.503997 0 l
+291.504 0 l
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2146103004
Review-Url: https://codereview.chromium.org/2146103004
diff --git a/src/pdf/SkPDFUtils.cpp b/src/pdf/SkPDFUtils.cpp
index 9e4ac51..0fe6fb5 100644
--- a/src/pdf/SkPDFUtils.cpp
+++ b/src/pdf/SkPDFUtils.cpp
@@ -282,6 +282,39 @@
stream->write(result, len);
}
+// Return pow(10.0, e), optimized for common cases.
+inline double pow10(int e) {
+ switch (e) {
+ case 0: return 1.0; // common cases
+ case 1: return 10.0;
+ case 2: return 100.0;
+ case 3: return 1e+03;
+ case 4: return 1e+04;
+ case 5: return 1e+05;
+ case 6: return 1e+06;
+ case 7: return 1e+07;
+ case 8: return 1e+08;
+ case 9: return 1e+09;
+ case 10: return 1e+10;
+ case 11: return 1e+11;
+ case 12: return 1e+12;
+ case 13: return 1e+13;
+ case 14: return 1e+14;
+ case 15: return 1e+15;
+ default:
+ if (e > 15) {
+ double value = 1e+15;
+ while (e-- > 15) { value *= 10.0; }
+ return value;
+ } else {
+ SkASSERT(e < 0);
+ double value = 1.0;
+ while (e++ < 0) { value /= 10.0; }
+ return value;
+ }
+ }
+}
+
/** Write a string into result, includeing a terminating '\0' (for
unit testing). Return strlen(result) (for SkWStream::write) The
resulting string will be in the form /[-]?([0-9]*.)?[0-9]+/ and
@@ -327,65 +360,74 @@
*output = '\0';
return output - result;
}
- // Inspired by:
- // http://www.exploringbinary.com/quick-and-dirty-floating-point-to-decimal-conversion/
-
if (value < 0.0) {
*output++ = '-';
value = -value;
}
SkASSERT(value >= 0.0f);
- // Must use double math to keep precision right.
- double intPart;
- double fracPart = std::modf(static_cast<double>(value), &intPart);
- SkASSERT(intPart + fracPart == static_cast<double>(value));
- size_t significantDigits = 0;
- const size_t maxSignificantDigits = 9;
- // Any fewer significant digits loses precision. The unit test
- // checks round-trip correctness.
- SkASSERT(intPart >= 0.0 && fracPart >= 0.0); // negative handled already.
- SkASSERT(intPart > 0.0 || fracPart > 0.0); // zero already caught.
- if (intPart > 0.0) {
- // put the intPart digits onto a stack for later reversal.
- char reversed[1 + FLT_MAX_10_EXP]; // 39 == 1 + FLT_MAX_10_EXP
- // the largest integer part is FLT_MAX; it has 39 decimal digits.
- size_t reversedIndex = 0;
- do {
- SkASSERT(reversedIndex < sizeof(reversed));
- int digit = static_cast<int>(std::fmod(intPart, 10.0));
- SkASSERT(digit >= 0 && digit <= 9);
- reversed[reversedIndex++] = '0' + digit;
- intPart = std::floor(intPart / 10.0);
- } while (intPart > 0.0);
- significantDigits = reversedIndex;
- SkASSERT(reversedIndex <= sizeof(reversed));
- SkASSERT(output + reversedIndex <= end);
- while (reversedIndex-- > 0) { // pop from stack, append to result
- *output++ = reversed[reversedIndex];
- }
+ int binaryExponent;
+ (void)std::frexp(value, &binaryExponent);
+ static const double kLog2 = 0.3010299956639812; // log10(2.0);
+ int decimalExponent = static_cast<int>(std::floor(kLog2 * binaryExponent));
+ int decimalShift = decimalExponent - 8;
+ double power = pow10(-decimalShift);
+ int32_t d = static_cast<int32_t>(value * power + 0.5);
+ // SkASSERT(value == (float)(d * pow(10.0, decimalShift)));
+ SkASSERT(d <= 999999999);
+ if (d > 167772159) { // floor(pow(10,1+log10(1<<24)))
+ // need one fewer decimal digits for 24-bit precision.
+ decimalShift = decimalExponent - 7;
+ // SkASSERT(power * 0.1 = pow10(-decimalShift));
+ // recalculate to get rounding right.
+ d = static_cast<int32_t>(value * (power * 0.1) + 0.5);
+ SkASSERT(d <= 99999999);
}
- if (fracPart > 0 && significantDigits < maxSignificantDigits) {
- *output++ = '.';
- SkASSERT(output <= end);
+ while (d % 10 == 0) {
+ d /= 10;
+ ++decimalShift;
+ }
+ SkASSERT(d > 0);
+ // SkASSERT(value == (float)(d * pow(10.0, decimalShift)));
+ uint8_t buffer[9]; // decimal value buffer.
+ int bufferIndex = 0;
+ do {
+ buffer[bufferIndex++] = d % 10;
+ d /= 10;
+ } while (d != 0);
+ SkASSERT(bufferIndex <= (int)sizeof(buffer) && bufferIndex > 0);
+ if (decimalShift >= 0) {
do {
- fracPart = std::modf(fracPart * 10.0, &intPart);
- int digit = static_cast<int>(intPart);
- SkASSERT(digit >= 0 && digit <= 9);
- *output++ = '0' + digit;
- SkASSERT(output <= end);
- if (digit > 0 || significantDigits > 0) {
- // start counting significantDigits after first non-zero digit.
- ++significantDigits;
+ --bufferIndex;
+ *output++ = '0' + buffer[bufferIndex];
+ } while (bufferIndex);
+ for (int i = 0; i < decimalShift; ++i) {
+ *output++ = '0';
+ }
+ } else {
+ int placesBeforeDecimal = bufferIndex + decimalShift;
+ if (placesBeforeDecimal > 0) {
+ while (placesBeforeDecimal-- > 0) {
+ --bufferIndex;
+ *output++ = '0' + buffer[bufferIndex];
}
- } while (fracPart > 0.0
- && significantDigits < maxSignificantDigits
- && output < end);
- // When fracPart == 0, additional digits will be zero.
- // When significantDigits == maxSignificantDigits, we can stop.
- // when output == end, we have filed the string.
- // Note: denormalized numbers will not have the same number of
- // significantDigits, but do not need them to round-trip.
+ *output++ = '.';
+ } else {
+ *output++ = '.';
+ int placesAfterDecimal = -placesBeforeDecimal;
+ while (placesAfterDecimal-- > 0) {
+ *output++ = '0';
+ }
+ }
+ while (bufferIndex > 0) {
+ --bufferIndex;
+ *output++ = '0' + buffer[bufferIndex];
+ if (output == end) {
+ break; // denormalized: don't need extra precision.
+ // Note: denormalized numbers will not have the same number of
+ // significantDigits, but do not need them to round-trip.
+ }
+ }
}
SkASSERT(output <= end);
*output = '\0';
diff --git a/tests/PDFPrimitivesTest.cpp b/tests/PDFPrimitivesTest.cpp
index d816b60..cef1150 100644
--- a/tests/PDFPrimitivesTest.cpp
+++ b/tests/PDFPrimitivesTest.cpp
@@ -27,6 +27,9 @@
#include "Test.h"
#include "sk_tool_utils.h"
+#include <cstdlib>
+#include <cmath>
+
#define DUMMY_TEXT "DCT compessed stream."
namespace {
@@ -44,9 +47,8 @@
catPtr = &catalog;
}
obj.emitObject(&buffer, catPtr->numbers, catPtr->substitutes);
- SkAutoTDelete<SkStreamAsset> asset(buffer.detachAsStream());
- SkString tmp(asset->getLength());
- asset->read(tmp.writable_str(), asset->getLength());
+ SkString tmp(buffer.bytesWritten());
+ buffer.copyTo(tmp.writable_str());
return tmp;
}
@@ -54,42 +56,41 @@
return len == str.size() && 0 == memcmp(str.c_str(), strPtr, len);
}
-#define ASSERT_EQL(REPORTER, SKSTRING, STRING, LEN) \
- do { \
- const char* strptr = STRING; \
- const SkString& sks = SKSTRING; \
- if (!eq(sks, strptr, LEN)) { \
- REPORT_FAILURE( \
- REPORTER, \
- "", \
- SkStringPrintf("'%s' != '%s'", strptr, sks.c_str())); \
- } \
- } while (false)
+static void assert_eql(skiatest::Reporter* reporter,
+ const SkString& skString,
+ const char* str,
+ size_t len) {
+ if (!eq(skString, str, len)) {
+ REPORT_FAILURE(reporter, "", SkStringPrintf(
+ "'%*s' != '%s'", len, str, skString.c_str()));
+ }
+}
-#define ASSERT_EQ(REPORTER, SKSTRING, STRING) \
- do { \
- const char* str = STRING; \
- ASSERT_EQL(REPORTER, SKSTRING, str, strlen(str)); \
- } while (false)
-
-#define ASSERT_EMIT_EQ(REPORTER, OBJECT, STRING) \
- do { \
- SkString result = emit_to_string(OBJECT); \
- ASSERT_EQ(REPORTER, result, STRING); \
- } while (false)
+static void assert_eq(skiatest::Reporter* reporter,
+ const SkString& skString,
+ const char* str) {
+ assert_eql(reporter, skString, str, strlen(str));
+}
+template <typename T>
+static void assert_emit_eq(skiatest::Reporter* reporter,
+ T& object,
+ const char* string) {
+ SkString result = emit_to_string(object);
+ assert_eq(reporter, result, string);
+}
static void TestPDFStream(skiatest::Reporter* reporter) {
char streamBytes[] = "Test\nFoo\tBar";
SkAutoTDelete<SkMemoryStream> streamData(new SkMemoryStream(
streamBytes, strlen(streamBytes), true));
sk_sp<SkPDFStream> stream(new SkPDFStream(streamData.get()));
- ASSERT_EMIT_EQ(reporter,
+ assert_emit_eq(reporter,
*stream,
"<</Length 12>> stream\nTest\nFoo\tBar\nendstream");
stream->insertInt("Attribute", 42);
- ASSERT_EMIT_EQ(reporter,
+ assert_emit_eq(reporter,
*stream,
"<</Length 12\n/Attribute 42>> stream\n"
"Test\nFoo\tBar\nendstream");
@@ -115,7 +116,7 @@
expected.writeText("\nendstream");
SkAutoDataUnref expectedResultData2(expected.copyToData());
SkString result = emit_to_string(*stream);
- ASSERT_EQL(reporter,
+ assert_eql(reporter,
result,
(const char*)expectedResultData2->data(),
expectedResultData2->size());
@@ -154,7 +155,7 @@
SkString result = emit_to_string(*a2, &catalog);
// If appendObjRef misbehaves, then the result would
// be [[]], not [1 0 R].
- ASSERT_EQ(reporter, result, "[1 0 R]");
+ assert_eq(reporter, result, "[1 0 R]");
}
static void TestSubstitute(skiatest::Reporter* reporter) {
@@ -190,91 +191,94 @@
doc->close();
}
+static void assert_emit_eq_number(skiatest::Reporter* reporter, float number) {
+ SkPDFUnion pdfUnion = SkPDFUnion::Scalar(number);
+ SkString result = emit_to_string(pdfUnion);
+ float value = static_cast<float>(std::atof(result.c_str()));
+ if (value != number) {
+ ERRORF(reporter, "%.9g != %s", number, result.c_str());
+ }
+}
+
+
static void TestPDFUnion(skiatest::Reporter* reporter) {
SkPDFUnion boolTrue = SkPDFUnion::Bool(true);
- ASSERT_EMIT_EQ(reporter, boolTrue, "true");
+ assert_emit_eq(reporter, boolTrue, "true");
SkPDFUnion boolFalse = SkPDFUnion::Bool(false);
- ASSERT_EMIT_EQ(reporter, boolFalse, "false");
+ assert_emit_eq(reporter, boolFalse, "false");
SkPDFUnion int42 = SkPDFUnion::Int(42);
- ASSERT_EMIT_EQ(reporter, int42, "42");
+ assert_emit_eq(reporter, int42, "42");
- SkPDFUnion realHalf = SkPDFUnion::Scalar(SK_ScalarHalf);
- ASSERT_EMIT_EQ(reporter, realHalf, ".5");
-
- SkPDFUnion bigScalar = SkPDFUnion::Scalar(110999.75f);
- ASSERT_EMIT_EQ(reporter, bigScalar, "110999.75");
-
- SkPDFUnion biggerScalar = SkPDFUnion::Scalar(50000000.1f);
- ASSERT_EMIT_EQ(reporter, biggerScalar, "50000000");
-
- SkPDFUnion smallestScalar = SkPDFUnion::Scalar(1.0f / 65536);
- ASSERT_EMIT_EQ(reporter, smallestScalar, ".0000152587890");
+ assert_emit_eq_number(reporter, SK_ScalarHalf);
+ assert_emit_eq_number(reporter, 110999.75f); // bigScalar
+ assert_emit_eq_number(reporter, 50000000.1f); // biggerScalar
+ assert_emit_eq_number(reporter, 1.0f / 65536); // smallScalar
SkPDFUnion stringSimple = SkPDFUnion::String("test ) string ( foo");
- ASSERT_EMIT_EQ(reporter, stringSimple, "(test \\) string \\( foo)");
+ assert_emit_eq(reporter, stringSimple, "(test \\) string \\( foo)");
SkString stringComplexInput("\ttest ) string ( foo");
SkPDFUnion stringComplex = SkPDFUnion::String(stringComplexInput);
- ASSERT_EMIT_EQ(reporter, stringComplex, "(\\011test \\) string \\( foo)");
+ assert_emit_eq(reporter, stringComplex, "(\\011test \\) string \\( foo)");
SkString binaryStringInput("\1\2\3\4\5\6\7\10\11\12\13\14\15\16\17\20");
SkPDFUnion binaryString = SkPDFUnion::String(binaryStringInput);
- ASSERT_EMIT_EQ(reporter, binaryString, "<0102030405060708090A0B0C0D0E0F10>");
+ assert_emit_eq(reporter, binaryString, "<0102030405060708090A0B0C0D0E0F10>");
SkString nameInput("Test name\twith#tab");
SkPDFUnion name = SkPDFUnion::Name(nameInput);
- ASSERT_EMIT_EQ(reporter, name, "/Test#20name#09with#23tab");
+ assert_emit_eq(reporter, name, "/Test#20name#09with#23tab");
SkString nameInput2("A#/%()<>[]{}B");
SkPDFUnion name2 = SkPDFUnion::Name(nameInput2);
- ASSERT_EMIT_EQ(reporter, name2, "/A#23#2F#25#28#29#3C#3E#5B#5D#7B#7DB");
+ assert_emit_eq(reporter, name2, "/A#23#2F#25#28#29#3C#3E#5B#5D#7B#7DB");
SkPDFUnion name3 = SkPDFUnion::Name("SimpleNameWithOnlyPrintableASCII");
- ASSERT_EMIT_EQ(reporter, name3, "/SimpleNameWithOnlyPrintableASCII");
+ assert_emit_eq(reporter, name3, "/SimpleNameWithOnlyPrintableASCII");
// Test that we correctly handle characters with the high-bit set.
SkString highBitString("\xDE\xAD" "be\xEF");
SkPDFUnion highBitName = SkPDFUnion::Name(highBitString);
- ASSERT_EMIT_EQ(reporter, highBitName, "/#DE#ADbe#EF");
+ assert_emit_eq(reporter, highBitName, "/#DE#ADbe#EF");
}
static void TestPDFArray(skiatest::Reporter* reporter) {
sk_sp<SkPDFArray> array(new SkPDFArray);
- ASSERT_EMIT_EQ(reporter, *array, "[]");
+ assert_emit_eq(reporter, *array, "[]");
array->appendInt(42);
- ASSERT_EMIT_EQ(reporter, *array, "[42]");
+ assert_emit_eq(reporter, *array, "[42]");
array->appendScalar(SK_ScalarHalf);
- ASSERT_EMIT_EQ(reporter, *array, "[42 .5]");
+ assert_emit_eq(reporter, *array, "[42 .5]");
array->appendInt(0);
- ASSERT_EMIT_EQ(reporter, *array, "[42 .5 0]");
+ assert_emit_eq(reporter, *array, "[42 .5 0]");
array->appendBool(true);
- ASSERT_EMIT_EQ(reporter, *array, "[42 .5 0 true]");
+ assert_emit_eq(reporter, *array, "[42 .5 0 true]");
array->appendName("ThisName");
- ASSERT_EMIT_EQ(reporter, *array, "[42 .5 0 true /ThisName]");
+ assert_emit_eq(reporter, *array, "[42 .5 0 true /ThisName]");
array->appendName(SkString("AnotherName"));
- ASSERT_EMIT_EQ(reporter, *array, "[42 .5 0 true /ThisName /AnotherName]");
+ assert_emit_eq(reporter, *array, "[42 .5 0 true /ThisName /AnotherName]");
array->appendString("This String");
- ASSERT_EMIT_EQ(reporter, *array,
+ assert_emit_eq(reporter, *array,
"[42 .5 0 true /ThisName /AnotherName (This String)]");
array->appendString(SkString("Another String"));
- ASSERT_EMIT_EQ(reporter, *array,
+ assert_emit_eq(reporter, *array,
"[42 .5 0 true /ThisName /AnotherName (This String) "
"(Another String)]");
sk_sp<SkPDFArray> innerArray(new SkPDFArray);
innerArray->appendInt(-1);
array->appendObject(std::move(innerArray));
- ASSERT_EMIT_EQ(reporter, *array,
+ assert_emit_eq(reporter, *array,
"[42 .5 0 true /ThisName /AnotherName (This String) "
"(Another String) [-1]]");
@@ -286,23 +290,23 @@
array->appendObjRef(std::move(referencedArray));
SkString result = emit_to_string(*array, &catalog);
- ASSERT_EQ(reporter, result,
+ assert_eq(reporter, result,
"[42 .5 0 true /ThisName /AnotherName (This String) "
"(Another String) [-1] 1 0 R]");
}
static void TestPDFDict(skiatest::Reporter* reporter) {
sk_sp<SkPDFDict> dict(new SkPDFDict);
- ASSERT_EMIT_EQ(reporter, *dict, "<<>>");
+ assert_emit_eq(reporter, *dict, "<<>>");
dict->insertInt("n1", SkToSizeT(42));
- ASSERT_EMIT_EQ(reporter, *dict, "<</n1 42>>");
+ assert_emit_eq(reporter, *dict, "<</n1 42>>");
dict.reset(new SkPDFDict);
- ASSERT_EMIT_EQ(reporter, *dict, "<<>>");
+ assert_emit_eq(reporter, *dict, "<<>>");
dict->insertInt("n1", 42);
- ASSERT_EMIT_EQ(reporter, *dict, "<</n1 42>>");
+ assert_emit_eq(reporter, *dict, "<</n1 42>>");
dict->insertScalar("n2", SK_ScalarHalf);
@@ -310,37 +314,37 @@
sk_sp<SkPDFArray> innerArray(new SkPDFArray);
innerArray->appendInt(-100);
dict->insertObject(n3, std::move(innerArray));
- ASSERT_EMIT_EQ(reporter, *dict, "<</n1 42\n/n2 .5\n/n3 [-100]>>");
+ assert_emit_eq(reporter, *dict, "<</n1 42\n/n2 .5\n/n3 [-100]>>");
dict.reset(new SkPDFDict);
- ASSERT_EMIT_EQ(reporter, *dict, "<<>>");
+ assert_emit_eq(reporter, *dict, "<<>>");
dict->insertInt("n1", 24);
- ASSERT_EMIT_EQ(reporter, *dict, "<</n1 24>>");
+ assert_emit_eq(reporter, *dict, "<</n1 24>>");
dict->insertInt("n2", SkToSizeT(99));
- ASSERT_EMIT_EQ(reporter, *dict, "<</n1 24\n/n2 99>>");
+ assert_emit_eq(reporter, *dict, "<</n1 24\n/n2 99>>");
dict->insertScalar("n3", SK_ScalarHalf);
- ASSERT_EMIT_EQ(reporter, *dict, "<</n1 24\n/n2 99\n/n3 .5>>");
+ assert_emit_eq(reporter, *dict, "<</n1 24\n/n2 99\n/n3 .5>>");
dict->insertName("n4", "AName");
- ASSERT_EMIT_EQ(reporter, *dict, "<</n1 24\n/n2 99\n/n3 .5\n/n4 /AName>>");
+ assert_emit_eq(reporter, *dict, "<</n1 24\n/n2 99\n/n3 .5\n/n4 /AName>>");
dict->insertName("n5", SkString("AnotherName"));
- ASSERT_EMIT_EQ(reporter, *dict, "<</n1 24\n/n2 99\n/n3 .5\n/n4 /AName\n"
+ assert_emit_eq(reporter, *dict, "<</n1 24\n/n2 99\n/n3 .5\n/n4 /AName\n"
"/n5 /AnotherName>>");
dict->insertString("n6", "A String");
- ASSERT_EMIT_EQ(reporter, *dict, "<</n1 24\n/n2 99\n/n3 .5\n/n4 /AName\n"
+ assert_emit_eq(reporter, *dict, "<</n1 24\n/n2 99\n/n3 .5\n/n4 /AName\n"
"/n5 /AnotherName\n/n6 (A String)>>");
dict->insertString("n7", SkString("Another String"));
- ASSERT_EMIT_EQ(reporter, *dict, "<</n1 24\n/n2 99\n/n3 .5\n/n4 /AName\n"
+ assert_emit_eq(reporter, *dict, "<</n1 24\n/n2 99\n/n3 .5\n/n4 /AName\n"
"/n5 /AnotherName\n/n6 (A String)\n/n7 (Another String)>>");
dict.reset(new SkPDFDict("DType"));
- ASSERT_EMIT_EQ(reporter, *dict, "<</Type /DType>>");
+ assert_emit_eq(reporter, *dict, "<</Type /DType>>");
sk_sp<SkPDFArray> referencedArray(new SkPDFArray);
Catalog catalog;
@@ -349,7 +353,7 @@
referencedArray.get()) == 1);
dict->insertObjRef("n1", std::move(referencedArray));
SkString result = emit_to_string(*dict, &catalog);
- ASSERT_EQ(reporter, result, "<</Type /DType\n/n1 1 0 R>>");
+ assert_eq(reporter, result, "<</Type /DType\n/n1 1 0 R>>");
}
DEF_TEST(PDFPrimitives, reporter) {
@@ -465,7 +469,7 @@
ERRORF(reporter, "unscannable result: %s", floatString);
return;
}
- if (isfinite(inputFloat) && roundTripFloat != inputFloat) {
+ if (std::isfinite(inputFloat) && roundTripFloat != inputFloat) {
ERRORF(reporter, "roundTripFloat (%.9g) != inputFloat (%.9g)",
roundTripFloat, inputFloat);
}