Skip to content

Chracter spacing #30

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
Vladimir-Burshnev wants to merge 2 commits into
base: customizations-for-tagged-pdf
Choose a base branch
from
Open

Chracter spacing #30

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
b82597b
Wrong bbox in location for vertical font (character spasing)
Jul 1, 2026
dceee0c
Ensure consistency with the backend
Jul 14, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
137 changes: 37 additions & 100 deletions src/core/bounding_boxes.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -52,133 +52,70 @@ class BoundingBoxesCalculator {
}

getTextBoundingBox(glyphs) {
let tx = 0;
let ty = 0;
// Save previous x value to take it into account while calculating
// width of marked content

const ctm = this.graphicsStateManager.state.ctm;
const textState = this.textStateManager.state;
const {
fontMatrix, textMatrix, textHScale, fontSize,
font, textRise, charSpacing, wordSpacing,
} = textState;
const scaledFontSize = textHScale * fontSize;

const descent =
(this.textStateManager.state.font.descent || 0) *
this.textStateManager.state.fontSize;
const ascent =
(this.textStateManager.state.font.ascent || 1) *
this.textStateManager.state.fontSize;
const rise =
this.textStateManager.state.textRise *
this.textStateManager.state.fontSize;
const descent = (font.descent || 0) * fontSize;
const ascent = (font.ascent || 1) * fontSize;
const rise = textRise * fontSize;

let tx0, ty0, shift, height;
if (!this.textStateManager.state.font.vertical) {
if (!font.vertical) {
// Left Bottom point of text bbox
// Save before text matrix will be changed with going through glyphs
[tx0, ty0] = this.transformPoint(
0,
descent + rise,
this.textStateManager.state.textMatrix
);
[tx0, ty0] = this.transformPoint(0, descent + rise, textMatrix);
// Calculate transformed height and shift to place
// the whole glyph inside the bbox
shift = [
tx0 - this.textStateManager.state.textMatrix[4],
ty0 - this.textStateManager.state.textMatrix[5],
];
height = this.transformPoint(
0,
ascent - descent,
this.textStateManager.state.textMatrix
);
shift = [tx0 - textMatrix[4], ty0 - textMatrix[5]];
height = this.transformPoint(0, ascent - descent, textMatrix);
} else {
[tx0, ty0] = this.transformPoint(
-this.textStateManager.state.fontSize / 2,
rise,
this.textStateManager.state.textMatrix
);
shift = [
tx0 - this.textStateManager.state.textMatrix[4],
ty0 - this.textStateManager.state.textMatrix[5],
];
height = this.transformPoint(
ascent - descent,
0,
this.textStateManager.state.textMatrix
);
[tx0, ty0] = this.transformPoint(-scaledFontSize / 2, rise, textMatrix);
shift = [tx0 - textMatrix[4], ty0 - textMatrix[5]];
height = this.transformPoint(scaledFontSize, 0, textMatrix);
}
height[0] -= this.textStateManager.state.textMatrix[4];
height[1] -= this.textStateManager.state.textMatrix[5];
height[0] -= textMatrix[4];
height[1] -= textMatrix[5];
height = Math.hypot(height[0], height[1]);
height *=
this.textStateManager.state.textMatrix[0] *
this.textStateManager.state.textMatrix[3] <
0
? -1
: 1;
height *= textMatrix[0] * textMatrix[3] < 0 ? -1 : 1;

let glyphsSize = [];
let tx = 0, ty = 0;
for (let i = 0; i < glyphs.length; i++) {
textState.translateTextMatrix(tx, -ty);
tx = ty = 0;
const glyph = glyphs[i];
if (typeof glyph === "number") {
if (this.textStateManager.state.font.vertical) {
ty =
(-glyph / 1000) *
this.textStateManager.state.fontSize *
this.textStateManager.state.textHScale;
if (!font.vertical) {
tx = (-glyph / 1000) * scaledFontSize;
} else {
tx =
(-glyph / 1000) *
this.textStateManager.state.fontSize *
this.textStateManager.state.textHScale;
ty = (glyph / 1000) * fontSize;
}
} else {
let glyphWidth = null;
glyphWidth =
this.textStateManager.state.font.vertical && glyph.vmetric
? glyph.vmetric[0]
: glyph.width;
if (!this.textStateManager.state.font.vertical) {
const w0 =
glyphWidth *
(this.textStateManager.state.fontMatrix
? this.textStateManager.state.fontMatrix[0]
: 1 / 1000);
tx =
(w0 * this.textStateManager.state.fontSize +
this.textStateManager.state.charSpacing +
(glyph.isSpace ? this.textStateManager.state.wordSpacing : 0)) *
this.textStateManager.state.textHScale;
const vmetric = glyph.vmetric ?? font.defaultVMetrics;
const glyphWidth = font.vertical && vmetric ? -vmetric[0] : glyph.width;
const [x, y] = [textMatrix[4] + shift[0], textMatrix[5] + shift[1]];
if (!font.vertical) {
const w0 = glyphWidth * (fontMatrix ? fontMatrix[0] : 1 / 1000);
textState.translateTextMatrix(w0 * scaledFontSize, 0);
tx = (charSpacing + (glyph.isSpace ? wordSpacing : 0)) * textHScale;
} else {
const w1 =
glyphWidth *
(this.textStateManager.state.fontMatrix
? this.textStateManager.state.fontMatrix[0]
: 1 / 1000);
ty =
w1 * this.textStateManager.state.fontSize -
this.textStateManager.state.charSpacing -
(glyph.isSpace ? this.textStateManager.state.wordSpacing : 0);
const w1 = glyphWidth * (fontMatrix ? fontMatrix[0] : 1 / 1000);
textState.translateTextMatrix(0, -w1 * fontSize);
ty = -charSpacing - (glyph.isSpace ? wordSpacing : 0);
}
}
const [x, y] = [
this.textStateManager.state.textMatrix[4] + shift[0],
this.textStateManager.state.textMatrix[5] + shift[1],
];
this.textStateManager.state.translateTextMatrix(tx, -ty);
if (typeof glyph !== "number") {
glyphsSize.push([
x,
y,
this.textStateManager.state.textMatrix[4] + shift[0],
this.textStateManager.state.textMatrix[5] + shift[1],
]);
glyphsSize.push([x, y, textMatrix[4] + shift[0], textMatrix[5] + shift[1]]);
}
}

// Right Bottom point is in text matrix after going through glyphs
const [tx1, ty1] = [
this.textStateManager.state.textMatrix[4] + shift[0],
this.textStateManager.state.textMatrix[5] + shift[1],
];
const [tx1, ty1] = [textMatrix[4] + shift[0], textMatrix[5] + shift[1]];
// Top point can be calculated from base and height
const [tx2, ty2, tx3, ty3] = this.getTopPoints(tx0, ty0, tx1, ty1, height);
glyphsSize = glyphsSize.map(glyphSize => [
Expand Down
Loading