Skip to content
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

Fix zoom issue with too thin lines #12869

Merged
merged 1 commit into from
Jan 21, 2021
Merged

Fix zoom issue with too thin lines #12869

Changes from all commits
Commits
Show all changes
1 commit
Select commit
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
43 changes: 27 additions & 16 deletions src/display/canvas.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -923,6 +923,10 @@ const CanvasGraphics = (function CanvasGraphicsClosure() {
this.ctx.transform.apply(this.ctx, viewport.transform);

this.baseTransform = this.ctx.mozCurrentTransform.slice();
this._combinedScaleFactor = Math.hypot(
this.baseTransform[0],
this.baseTransform[2]
);

if (this.imageLayer) {
this.imageLayer.beginLayout();
Expand Down Expand Up @@ -1357,22 +1361,23 @@ const CanvasGraphics = (function CanvasGraphicsClosure() {
const scale = Util.singularValueDecompose2dScale(transform)[0];
ctx.strokeStyle = strokeColor.getPattern(ctx, this);
const lineWidth = this.getSinglePixelWidth();
if (lineWidth === -1) {
const scaledLineWidth = this.current.lineWidth * scale;
if (lineWidth < 0 && -lineWidth >= scaledLineWidth) {
ctx.resetTransform();
ctx.lineWidth = 1;
ctx.lineWidth = Math.round(this._combinedScaleFactor);
} else {
ctx.lineWidth = Math.max(lineWidth, this.current.lineWidth * scale);
ctx.lineWidth = Math.max(lineWidth, scaledLineWidth);
}
ctx.stroke();
ctx.restore();
} else {
const lineWidth = this.getSinglePixelWidth();
if (lineWidth === -1) {
if (lineWidth < 0 && -lineWidth >= this.current.lineWidth) {
// The current transform will transform a square pixel into a
// parallelogram where both heights are lower than 1 and not equal.
ctx.save();
ctx.resetTransform();
ctx.lineWidth = 1;
ctx.lineWidth = Math.round(this._combinedScaleFactor);
ctx.stroke();
ctx.restore();
} else {
Expand Down Expand Up @@ -1621,7 +1626,7 @@ const CanvasGraphics = (function CanvasGraphicsClosure() {
) {
if (resetLineWidthToOne) {
ctx.resetTransform();
ctx.lineWidth = 1;
ctx.lineWidth = Math.round(this._combinedScaleFactor);
}
ctx.stroke();
}
Expand All @@ -1641,7 +1646,7 @@ const CanvasGraphics = (function CanvasGraphicsClosure() {
ctx.save();
ctx.moveTo(x, y);
ctx.resetTransform();
ctx.lineWidth = 1;
ctx.lineWidth = Math.round(this._combinedScaleFactor);
ctx.strokeText(character, 0, 0);
ctx.restore();
} else {
Expand Down Expand Up @@ -1744,7 +1749,7 @@ const CanvasGraphics = (function CanvasGraphicsClosure() {
) {
this._cachedGetSinglePixelWidth = null;
lineWidth = this.getSinglePixelWidth();
resetLineWidthToOne = lineWidth === -1;
resetLineWidthToOne = lineWidth < 0;
}
} else {
lineWidth /= scale;
Expand Down Expand Up @@ -2664,25 +2669,31 @@ const CanvasGraphics = (function CanvasGraphicsClosure() {
// This is equivalent to:
// h = max(|line_1_inv(M)|, |line_2_inv(M)|)
const m = this.ctx.mozCurrentTransform;
const sqDet = (m[0] * m[3] - m[2] * m[1]) ** 2;

const absDet = Math.abs(m[0] * m[3] - m[2] * m[1]);
const sqNorm1 = m[0] ** 2 + m[2] ** 2;
const sqNorm2 = m[1] ** 2 + m[3] ** 2;
if (sqNorm1 !== sqNorm2 && (sqNorm1 > sqDet || sqNorm2 > sqDet)) {
// The parallelogram isn't a losange and at least one height
const pixelHeight = Math.sqrt(Math.max(sqNorm1, sqNorm2)) / absDet;
if (
sqNorm1 !== sqNorm2 &&
this._combinedScaleFactor * pixelHeight > 1
) {
// The parallelogram isn't a square and at least one height
// is lower than 1 so the resulting line width must be 1
// but it cannot be achieved with one scale: when scaling a pixel
// we'll get a rectangle (see issue #12295).
// For example with matrix [0.001 0, 0, 100], a pixel is transformed
// in a rectangle 0.001x100. If we just scale by 1000 (to have a 1)
// then we'll get a rectangle 1x1e5 which is wrong.
// In this case, we must reset the transform and set linewidth to 1
// In this case, we must reset the transform, set linewidth to 1
// and then stroke.
this._cachedGetSinglePixelWidth = -1;
} else if (sqDet > Number.EPSILON ** 2) {
this._cachedGetSinglePixelWidth = -(
this._combinedScaleFactor * pixelHeight
);
} else if (absDet > Number.EPSILON) {
// The multiplication by the constant 1.0000001 is here to have
// a number slightly greater than what we "exactly" want.
this._cachedGetSinglePixelWidth =
Math.sqrt(Math.max(sqNorm1, sqNorm2) / sqDet) * 1.0000001;
this._cachedGetSinglePixelWidth = pixelHeight * 1.0000001;
} else {
// Matrix is non-invertible.
this._cachedGetSinglePixelWidth = 1;
Expand Down