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[api-minor] Annotations - Adjust the font size in text field in considering the total width (bug 1721335)

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- it aims to fix #14502 and bug 1721335;
 - Acrobat and Pdfium do the same;
 - it'll avoid to have truncated data when printed;
 - change the factor to compute font size in using field height: lineHeight = 1.35*fontSize
  - this is the value used by Acrobat.
 - in order to not have truncated strings on the bottom, add few basic metrics for standard fonts.
This commit is contained in:
Calixte Denizet 2022-01-27 22:51:30 +01:00
parent 8f6965b197
commit ae842e1c3a
8 changed files with 214 additions and 40 deletions
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98
src/core/annotation.js
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@ -1523,13 +1523,15 @@ class WidgetAnnotation extends Annotation {
);
}
const font = await this._getFontData(evaluator, task);
const [defaultAppearance, fontSize] = this._computeFontSize(
totalHeight,
totalHeight - defaultPadding,
totalWidth - 2 * hPadding,
value,
font,
lineCount
);
const font = await this._getFontData(evaluator, task);
let descent = font.descent;
if (isNaN(descent)) {
descent = 0;
@ -1618,34 +1620,84 @@ class WidgetAnnotation extends Annotation {
return initialState.font;
}
_computeFontSize(height, lineCount) {
_getTextWidth(text, font) {
return (
font
.charsToGlyphs(text)
.reduce((width, glyph) => width + glyph.width, 0) / 1000
);
}
_computeFontSize(height, width, text, font, lineCount) {
let { fontSize } = this.data.defaultAppearanceData;
if (!fontSize) {
// A zero value for size means that the font shall be auto-sized:
// its size shall be computed as a function of the height of the
// annotation rectangle (see 12.7.3.3).
const roundWithOneDigit = x => Math.round(x * 10) / 10;
const roundWithTwoDigits = x => Math.floor(x * 100) / 100;
// Represent the percentage of the height of a single-line field over
// the font size.
// Acrobat seems to use this value.
const LINE_FACTOR = 1.35;
// Represent the percentage of the font size over the height
// of a single-line field.
const FONT_FACTOR = 0.8;
if (lineCount === -1) {
fontSize = roundWithOneDigit(FONT_FACTOR * height);
const textWidth = this._getTextWidth(text, font);
fontSize = roundWithTwoDigits(
Math.min(height / LINE_FACTOR, width / textWidth)
);
} else {
const lines = text.split(/\r\n?|\n/);
const cachedLines = [];
for (const line of lines) {
const encoded = font.encodeString(line).join("");
const glyphs = font.charsToGlyphs(encoded);
const positions = font.getCharPositions(encoded);
cachedLines.push({
line: encoded,
glyphs,
positions,
});
}
const isTooBig = fsize => {
// Return true when the text doesn't fit the given height.
let totalHeight = 0;
for (const cache of cachedLines) {
const chunks = this._splitLine(null, font, fsize, width, cache);
totalHeight += chunks.length * fsize;
if (totalHeight > height) {
return true;
}
}
return false;
};
// Hard to guess how many lines there are.
// The field may have been sized to have 10 lines
// and the user entered only 1 so if we get font size from
// height and number of lines then we'll get something too big.
// So we compute a fake number of lines based on height and
// a font size equal to 10.
// a font size equal to 12 (this is the default font size in
// Acrobat).
// Then we'll adjust font size to what we have really.
fontSize = 10;
let lineHeight = fontSize / FONT_FACTOR;
fontSize = 12;
let lineHeight = fontSize * LINE_FACTOR;
let numberOfLines = Math.round(height / lineHeight);
numberOfLines = Math.max(numberOfLines, lineCount);
lineHeight = height / numberOfLines;
fontSize = roundWithOneDigit(FONT_FACTOR * lineHeight);
while (true) {
lineHeight = height / numberOfLines;
fontSize = roundWithTwoDigits(lineHeight / LINE_FACTOR);
if (isTooBig(fontSize)) {
numberOfLines++;
continue;
}
break;
}
}
const { fontName, fontColor } = this.data.defaultAppearanceData;
@ -1660,13 +1712,7 @@ class WidgetAnnotation extends Annotation {
_renderText(text, font, fontSize, totalWidth, alignment, hPadding, vPadding) {
// We need to get the width of the text in order to align it correctly
const glyphs = font.charsToGlyphs(text);
const scale = fontSize / 1000;
let width = 0;
for (const glyph of glyphs) {
width += glyph.width * scale;
}
const width = this._getTextWidth(text, font) * fontSize;
let shift;
if (alignment === 1) {
// Center
@ -1803,7 +1849,7 @@ class TextWidgetAnnotation extends WidgetAnnotation {
hPadding,
vPadding
) {
const lines = text.split(/\r\n|\r|\n/);
const lines = text.split(/\r\n?|\n/);
const buf = [];
const totalWidth = width - 2 * hPadding;
for (const line of lines) {
@ -1833,18 +1879,18 @@ class TextWidgetAnnotation extends WidgetAnnotation {
);
}
_splitLine(line, font, fontSize, width) {
_splitLine(line, font, fontSize, width, cache = {}) {
// TODO: need to handle chars which are not in the font.
line = font.encodeString(line).join("");
line = cache.line || font.encodeString(line).join("");
const glyphs = font.charsToGlyphs(line);
const glyphs = cache.glyphs || font.charsToGlyphs(line);
if (glyphs.length <= 1) {
// Nothing to split
return [line];
}
const positions = font.getCharPositions(line);
const positions = cache.positions || font.getCharPositions(line);
const scale = fontSize / 1000;
const chunks = [];