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Font renderer - get int8 instead of uint8 in composite glyphes (bug 1749563)

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- it aims to fix https://bugzilla.mozilla.org/show_bug.cgi?id=1749563;
 - use some helper functions to get (u|i)int** values in buffer: it helps to have a clearer code;
 - in composite glyphes the translations values with a transformations are signed so consequently get some int8 instead of uint8;
 - add few TODOs.
This commit is contained in:
Calixte Denizet 2022-01-15 23:41:18 +01:00
parent da953f4b64
commit 74f25d2755
4 changed files with 96 additions and 65 deletions
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137
src/core/font_renderer.js
View File

@ -25,19 +25,34 @@ import { getGlyphsUnicode } from "./glyphlist.js";
import { StandardEncoding } from "./encodings.js";
import { Stream } from "./stream.js";
function getLong(data, offset) {
// TODO: use DataView and its methods.
function getUint32(data, offset) {
return (
(data[offset] << 24) |
(data[offset + 1] << 16) |
(data[offset + 2] << 8) |
data[offset + 3]
((data[offset] << 24) |
(data[offset + 1] << 16) |
(data[offset + 2] << 8) |
data[offset + 3]) >>>
0
);
}
function getUshort(data, offset) {
function getUint16(data, offset) {
return (data[offset] << 8) | data[offset + 1];
}
function getInt16(data, offset) {
return ((data[offset] << 24) | (data[offset + 1] << 16)) >> 16;
}
function getInt8(data, offset) {
return (data[offset] << 24) >> 24;
}
function getFloat214(data, offset) {
return getInt16(data, offset) / 16384;
}
function getSubroutineBias(subrs) {
const numSubrs = subrs.length;
let bias = 32768;
@ -51,48 +66,48 @@ function getSubroutineBias(subrs) {
function parseCmap(data, start, end) {
const offset =
getUshort(data, start + 2) === 1
? getLong(data, start + 8)
: getLong(data, start + 16);
const format = getUshort(data, start + offset);
getUint16(data, start + 2) === 1
? getUint32(data, start + 8)
: getUint32(data, start + 16);
const format = getUint16(data, start + offset);
let ranges, p, i;
if (format === 4) {
getUshort(data, start + offset + 2); // length
const segCount = getUshort(data, start + offset + 6) >> 1;
getUint16(data, start + offset + 2); // length
const segCount = getUint16(data, start + offset + 6) >> 1;
p = start + offset + 14;
ranges = [];
for (i = 0; i < segCount; i++, p += 2) {
ranges[i] = { end: getUshort(data, p) };
ranges[i] = { end: getUint16(data, p) };
}
p += 2;
for (i = 0; i < segCount; i++, p += 2) {
ranges[i].start = getUshort(data, p);
ranges[i].start = getUint16(data, p);
}
for (i = 0; i < segCount; i++, p += 2) {
ranges[i].idDelta = getUshort(data, p);
ranges[i].idDelta = getUint16(data, p);
}
for (i = 0; i < segCount; i++, p += 2) {
let idOffset = getUshort(data, p);
let idOffset = getUint16(data, p);
if (idOffset === 0) {
continue;
}
ranges[i].ids = [];
for (let j = 0, jj = ranges[i].end - ranges[i].start + 1; j < jj; j++) {
ranges[i].ids[j] = getUshort(data, p + idOffset);
ranges[i].ids[j] = getUint16(data, p + idOffset);
idOffset += 2;
}
}
return ranges;
} else if (format === 12) {
getLong(data, start + offset + 4); // length
const groups = getLong(data, start + offset + 12);
const groups = getUint32(data, start + offset + 12);
p = start + offset + 16;
ranges = [];
for (i = 0; i < groups; i++) {
start = getUint32(data, p);
ranges.push({
start: getLong(data, p),
end: getLong(data, p + 4),
idDelta: getLong(data, p + 8) - getLong(data, p),
start,
end: getUint32(data, p + 4),
idDelta: getUint32(data, p + 8) - start,
});
p += 12;
}
@ -126,19 +141,10 @@ function parseGlyfTable(glyf, loca, isGlyphLocationsLong) {
let itemSize, itemDecode;
if (isGlyphLocationsLong) {
itemSize = 4;
itemDecode = function fontItemDecodeLong(data, offset) {
return (
(data[offset] << 24) |
(data[offset + 1] << 16) |
(data[offset + 2] << 8) |
data[offset + 3]
);
};
itemDecode = getUint32;
} else {
itemSize = 2;
itemDecode = function fontItemDecode(data, offset) {
return (data[offset] << 9) | (data[offset + 1] << 1);
};
itemDecode = (data, offset) => 2 * getUint16(data, offset);
}
const glyphs = [];
let startOffset = itemDecode(loca, 0);
@ -187,7 +193,7 @@ function compileGlyf(code, cmds, font) {
}
let i = 0;
const numberOfContours = ((code[i] << 24) | (code[i + 1] << 16)) >> 16;
const numberOfContours = getInt16(code, i);
let flags;
let x = 0,
y = 0;
@ -195,45 +201,57 @@ function compileGlyf(code, cmds, font) {
if (numberOfContours < 0) {
// composite glyph
do {
flags = (code[i] << 8) | code[i + 1];
const glyphIndex = (code[i + 2] << 8) | code[i + 3];
flags = getUint16(code, i);
const glyphIndex = getUint16(code, i + 2);
i += 4;
let arg1, arg2;
if (flags & 0x01) {
arg1 = ((code[i] << 24) | (code[i + 1] << 16)) >> 16;
arg2 = ((code[i + 2] << 24) | (code[i + 3] << 16)) >> 16;
if (flags & 0x02) {
arg1 = getInt16(code, i);
arg2 = getInt16(code, i + 2);
} else {
arg1 = getUint16(code, i);
arg2 = getUint16(code, i + 2);
}
i += 4;
} else {
arg1 = code[i++];
arg2 = code[i++];
if (flags & 0x02) {
arg1 = getInt8(code, i++);
arg2 = getInt8(code, i++);
} else {
arg1 = code[i++];
arg2 = code[i++];
}
}
if (flags & 0x02) {
x = arg1;
y = arg2;
} else {
x = 0;
y = 0; // TODO "they are points" ?
y = 0;
}
let scaleX = 1,
scaleY = 1,
scale01 = 0,
scale10 = 0;
if (flags & 0x08) {
scaleX = scaleY = ((code[i] << 24) | (code[i + 1] << 16)) / 1073741824;
scaleX = scaleY = getFloat214(code, i);
i += 2;
} else if (flags & 0x40) {
scaleX = ((code[i] << 24) | (code[i + 1] << 16)) / 1073741824;
scaleY = ((code[i + 2] << 24) | (code[i + 3] << 16)) / 1073741824;
scaleX = getFloat214(code, i);
scaleY = getFloat214(code, i + 2);
i += 4;
} else if (flags & 0x80) {
scaleX = ((code[i] << 24) | (code[i + 1] << 16)) / 1073741824;
scale01 = ((code[i + 2] << 24) | (code[i + 3] << 16)) / 1073741824;
scale10 = ((code[i + 4] << 24) | (code[i + 5] << 16)) / 1073741824;
scaleY = ((code[i + 6] << 24) | (code[i + 7] << 16)) / 1073741824;
scaleX = getFloat214(code, i);
scale01 = getFloat214(code, i + 2);
scale10 = getFloat214(code, i + 4);
scaleY = getFloat214(code, i + 6);
i += 8;
}
const subglyph = font.glyphs[glyphIndex];
if (subglyph) {
// TODO: the transform should be applied only if there is a scale:
// https://github.com/freetype/freetype/blob/edd4fedc5427cf1cf1f4b045e53ff91eb282e9d4/src/truetype/ttgload.c#L1205
cmds.push(
{ cmd: "save" },
{
@ -241,6 +259,11 @@ function compileGlyf(code, cmds, font) {
args: [scaleX, scale01, scale10, scaleY, x, y],
}
);
if (!(flags & 0x02)) {
// TODO: we must use arg1 and arg2 to make something similar to:
// https://github.com/freetype/freetype/blob/edd4fedc5427cf1cf1f4b045e53ff91eb282e9d4/src/truetype/ttgload.c#L1209
}
compileGlyf(subglyph, cmds, font);
cmds.push({ cmd: "restore" });
}
@ -250,10 +273,10 @@ function compileGlyf(code, cmds, font) {
const endPtsOfContours = [];
let j, jj;
for (j = 0; j < numberOfContours; j++) {
endPtsOfContours.push((code[i] << 8) | code[i + 1]);
endPtsOfContours.push(getUint16(code, i));
i += 2;
}
const instructionLength = (code[i] << 8) | code[i + 1];
const instructionLength = getUint16(code, i);
i += 2 + instructionLength; // skipping the instructions
const numberOfPoints = endPtsOfContours[endPtsOfContours.length - 1] + 1;
const points = [];
@ -270,7 +293,7 @@ function compileGlyf(code, cmds, font) {
for (j = 0; j < numberOfPoints; j++) {
switch (points[j].flags & 0x12) {
case 0x00:
x += ((code[i] << 24) | (code[i + 1] << 16)) >> 16;
x += getInt16(code, i);
i += 2;
break;
case 0x02:
@ -285,7 +308,7 @@ function compileGlyf(code, cmds, font) {
for (j = 0; j < numberOfPoints; j++) {
switch (points[j].flags & 0x24) {
case 0x00:
y += ((code[i] << 24) | (code[i + 1] << 16)) >> 16;
y += getInt16(code, i);
i += 2;
break;
case 0x04:
@ -840,11 +863,11 @@ class FontRendererFactory {
static create(font, seacAnalysisEnabled) {
const data = new Uint8Array(font.data);
let cmap, glyf, loca, cff, indexToLocFormat, unitsPerEm;
const numTables = getUshort(data, 4);
const numTables = getUint16(data, 4);
for (let i = 0, p = 12; i < numTables; i++, p += 16) {
const tag = bytesToString(data.subarray(p, p + 4));
const offset = getLong(data, p + 8);
const length = getLong(data, p + 12);
const offset = getUint32(data, p + 8);
const length = getUint32(data, p + 12);
switch (tag) {
case "cmap":
cmap = parseCmap(data, offset, offset + length);
@ -856,8 +879,8 @@ class FontRendererFactory {
loca = data.subarray(offset, offset + length);
break;
case "head":
unitsPerEm = getUshort(data, offset + 18);
indexToLocFormat = getUshort(data, offset + 50);
unitsPerEm = getUint16(data, offset + 18);
indexToLocFormat = getUint16(data, offset + 50);
break;
case "CFF ":
cff = parseCff(data, offset, offset + length, seacAnalysisEnabled);

12
src/core/glyf.js
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@ -550,14 +550,12 @@ class CompositeGlyph {
pos += 4;
flags ^= ARG_1_AND_2_ARE_WORDS;
} else {
argument1 = glyf.getUint8(pos);
argument2 = glyf.getUint8(pos + 1);
if (flags & ARGS_ARE_XY_VALUES) {
const abs1 = argument1 & 0x7f;
argument1 = argument1 & 0x80 ? -abs1 : abs1;
const abs2 = argument2 & 0x7f;
argument2 = argument2 & 0x80 ? -abs2 : abs2;
argument1 = glyf.getInt8(pos);
argument2 = glyf.getInt8(pos + 1);
} else {
argument1 = glyf.getUint8(pos);
argument2 = glyf.getUint8(pos + 1);
}
pos += 2;
}

1
test/pdfs/bug1749563.pdf.link Normal file
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@ -0,0 +1 @@
https://bugzilla.mozilla.org/attachment.cgi?id=9258518

11
test/test_manifest.json
View File

@ -6215,5 +6215,14 @@
"rounds": 1,
"type": "eq",
"annotations": true
}
},
{ "id": "bug1749563",
"file": "pdfs/bug1749563.pdf",
"md5": "11294f6071a8dcc25b0e18953cee68fa",
"rounds": 1,
"link": true,
"firstPage": 1,
"lastPage": 1,
"type": "eq"
}
]