Path

A path object represents vector graphics, as if drawn by a pen. They can be used for stroking, filling or as a clip mask. The Path only determines the shape, not properties such as color, line width or line joins, etc.

A path contains a sequence of zero or more subpaths, each subpath consists of a sequence of zero or more basic operations which begins by a move to point and ends with a close:

• move to point, append by calling Path.prototype.moveTo()

• close subpath, append by calling Path.prototype.closePath()

• draw a straight line, append by calling Path.prototype.lineTo()

• draw a cubic Bézier curve, append by calling either of Path.prototype.curveTo(), Path.prototype.curveToV(), or Path.prototype.curveToY()

• draw a rectangle, append by calling Path.prototype.rect(), this is a subpath on its own and is equivalent to a move to a position, followed by drawing three lines and closing the subpath.

After a subpath is closed, the only operation that may be appended is a move to point, in order to start a new subpath. This is a requirement to ensure that an unclosed path always has a current point from which to start basic drawing operations.

Once all desired operations have been appended to a Path, its bounds can be determined, and it can be transformed. Finally, it’s possible to iterate over the basic path operations via Path.prototype.walk().

Constructors

class Path()

Create a new empty path.

var path = new mupdf.Path()

Instance methods

Path.prototype.closePath()

Append operation closing the current subpath by drawing a straight line to the point given in the last moveTo(). This also invalidates the current point, but a new one may be set by calling moveTo().

path.closePath()

Path.prototype.curveTo(x1, y1, x2, y2, x3, y3)

Append operation drawing a cubic Bézier curve from the current point to (x3, y3) using (x1, y1) and (x2, y2) as control points.

Arguments:

• x1 (number) – X1 coordinate.

• y1 (number) – Y1 coordinate.

• x2 (number) – X2 coordinate.

• y2 (number) – Y2 coordinate.

• x3 (number) – X3 coordinate.

• y3 (number) – Y3 coordinate.

path.curveTo(0, 0, 10, 10, 100, 100)

Path.prototype.curveToV(cx, cy, ex, ey)

Append operation drawing a cubic Bézier curve from the current point to (ex, ey) using the current point and (cx, cy) as control points. Will be converted to Path.prototype.curveTo() when appended to this Path.

Arguments:

• cx (number) – CX coordinate.

• cy (number) – CY coordinate.

• ex (number) – EX coordinate.

• ey (number) – EY coordinate.

path.curveToV(0, 0, 100, 100)

Path.prototype.curveToY(cx, cy, ex, ey)

Append operation drawing a cubic Bézier curve from the current point to (ex, ey) using the (cx, cy) and (ex, ey) as control points. Will be converted to Path.prototype.curveTo() when appended to this Path.

Arguments:

• cx (number) – CX coordinate.

• cy (number) – CY coordinate.

• ex (number) – EX coordinate.

• ey (number) – EY coordinate.

path.curveToY(0, 0, 100, 100)

Path.prototype.getBounds(strokeState, transform)

Return a bounding rectangle for the path.

Since the path does not describe properties such as line width, line joins, etc., the caller must provide a strokeState, containing those properties, to determine the bounds of path if it is stroked.

If no strokeState is provided, this call determines the bounds of the path if it is filled.

transform is applied to the points in the path while computing the bounds, but it is not applied to the points as stored in path, i.e. the Path is not altered.

Arguments:

• stroke (StrokeState | null) – The stroking properties to use.

• transform (Matrix) – A transform matrix applied to all points in path.

Returns:

Rect

var rect = path.getBounds(strokeState, mupdf.Matrix.identity)

Path.prototype.lineTo(x, y)

Append operation drawing a straight line from the current point to the given point.

Arguments:

• x (number) – X coordinate.

• y (number) – Y coordinate.

path.lineTo(20, 20)

Path.prototype.moveTo(x, y)

Append operation of lifting and moving the pen to the given point. This begins a new subpath and sets the current point.

Arguments:

• x (number) – X coordinate.

• y (number) – Y coordinate.

path.moveTo(10, 10)

Path.prototype.rect(x1, y1, x2, y2)

Shorthand for sequence:

moveTo(x1, y1)
lineTo(x2, y1)
lineTo(x2, y2)
lineto(x1, y2)
closePath()

Arguments:

• x1 (number) – X1 coordinate.

• y1 (number) – Y1 coordinate.

• x2 (number) – X2 coordinate.

• y2 (number) – Y2 coordinate.

path.rect(0, 0, 100, 100)

Path.prototype.transform(matrix)

Transform the path by applying the given transformation matrix.

This is done by transforming each point in all of the paths’ basic drawing operations.

Arguments:

• matrix (Matrix) – Transformation matrix to apply.

path.transform(mupdf.Matrix.scale(2, 2))

Path.prototype.walk(walker)

Iterate over all the basic drawing operations in this Path, calling a corresponding callback in the walker object passing the coordinates stored with the drawing operation.

Arguments:

• walker (PathWalker) – Object with callback functions.

function print(...args) {
        console.log(args.join(" "))
}

var pathPrinter = {
        moveTo: function (x, y) { print("moveTo", x, y) },
        lineTo: function (x, y) { print("lineTo", x, y) },
        curveTo: function (x1, y1, x2, y2, x3, y3) { print("curveTo", x1, y1, x2, y2, x3, y3) },
        closePath: function () { print("closePath") },
}

var traceDevice = {
        fillPath: function (path, evenOdd, ctm, colorSpace, color, alpha) {
                print("fillPath", evenOdd, ctm, colorSpace, color, alpha)
                path.walk(pathPrinter)
        },
        clipPath: function (path, evenOdd, ctm) {
                print("clipPath", evenOdd, ctm)
                path.walk(pathPrinter)
        },
        strokePath: function (path, stroke, ctm, colorSpace, color, alpha) {
                print("strokePath", JSON.stringify(stroke), ctm, colorSpace, color, alpha)
                path.walk(pathPrinter)
        },
        clipStrokePath: function (path, stroke, ctm) {
                print("clipStrokePath", JSON.stringify(stroke), ctm)
                path.walk(pathPrinter)
        }
}

var doc = mupdf.Document.openDocument(fs.readFileSync("test.pdf"), "application/pdf")
var page = doc.loadPage(0)
var device = new mupdf.Device(traceDevice)
page.run(device, mupdf.Matrix.identity)