js: Add Shade.bound function and bbox device example.

1 files changed, 91 insertions, 0 deletions

diff --git a/docs/examples/bbox-device.js b/docs/examples/bbox-device.js
new file mode 100644
index 00000000..52d2cb4a
--- /dev/null
+++ b/docs/examples/bbox-device.js
@@ -0,0 +1,91 @@
+function BBoxDevice(bbox) {
+	function extend(x,y) {
+		if (x < bbox[0]) bbox[0] = x;
+		if (x > bbox[2]) bbox[2] = x;
+		if (y < bbox[1]) bbox[1] = y;
+		if (y > bbox[3]) bbox[3] = y;
+	}
+	function extendPoint(m, px, py) {
+		var x = px * m[0] + py * m[2] + m[4];
+		var y = px * m[1] + py * m[3] + m[5];
+		extend(x, y);
+	}
+	function extendRect(m, r) {
+		var x0 = r[0], y0 = r[1];
+		var x1 = r[2], y1 = r[3];
+		extendPoint(m, x0, y0);
+		extendPoint(m, x1, y0);
+		extendPoint(m, x0, y1);
+		extendPoint(m, x1, y1);
+	}
+	function PathBounder(ctm) {
+		return {
+			moveTo: function (x,y) { extendPoint(ctm, x, y) },
+			lineTo: function (x,y) { extendPoint(ctm, x, y) },
+			curveTo: function (x1,y1,x2,y2,x3,y3) {
+				extendPoint(ctm, x1, y1);
+				extendPoint(ctm, x2, y2);
+				extendPoint(ctm, x3, y3);
+			},
+		};
+	}
+	function TextBounder(ctm) {
+		return {
+			showGlyph: function (font,trm,gid,ucs,wmode,bidi) {
+				var bbox = [ 0, -0.2, font.advanceGlyph(gid, 0), 0.8 ];
+				extendRect(Concat(trm, ctm), bbox);
+			},
+		};
+	}
+	return {
+		fillPath: function (path, evenOdd, ctm, colorSpace, color, alpha) {
+			path.walk(new PathBounder(ctm));
+		},
+		clipPath: function (path, evenOdd, ctm) {
+			path.walk(new PathBounder(ctm));
+		},
+		strokePath: function (path, stroke, ctm, colorSpace, color, alpha) {
+			path.walk(new PathBounder(ctm));
+		},
+		clipStrokePath: function (path, stroke, ctm) {
+			path.walk(new PathBounder(ctm));
+		},
+		fillText: function (text, ctm, colorSpace, color, alpha) {
+			text.walk(new TextBounder(ctm));
+		},
+		clipText: function (text, ctm) {
+			text.walk(new TextBounder(ctm));
+		},
+		strokeText: function (text, stroke, ctm, colorSpace, color, alpha) {
+			text.walk(new TextBounder(ctm));
+		},
+		clipStrokeText: function (text, stroke, ctm) {
+			text.walk(new TextBounder(ctm));
+		},
+		ignoreText: function (text, ctm) {
+			text.walk(new TextBounder(ctm));
+		},
+		fillShade: function (shade, ctm, alpha) {
+			var bbox = shade.bound(ctm);
+			extend(bbox[0], bbox[1]);
+			extend(bbox[2], bbox[3]);
+		},
+		fillImage: function (image, ctm, alpha) {
+			extendRect(ctm, [0,0,1,1]);
+		},
+		fillImageMask: function (image, ctm, colorSpace, color, alpha) {
+			extendRect(ctm, [0,0,1,1]);
+		},
+	};
+}
+
+if (argv.length != 3)
+	print("usage: mutool run bbox-device.js document.pdf pageNumber")
+else {
+	var doc = new Document(argv[1]);
+	var page = doc.loadPage(parseInt(argv[2])-1);
+	var bbox = [Infinity, Infinity, -Infinity, -Infinity];
+	page.run(new BBoxDevice(bbox), Identity);
+	print("original bbox:", page.bound());
+	print("computed bbox:", bbox.map(function (x) { return Math.round(x); }));
+}