From e08676c9e7036673aebf7617010fecd947ef91f3 Mon Sep 17 00:00:00 2001
From: Sebastian Rasmussen <sebras@gmail.com>
Date: Mon, 6 Feb 2012 02:00:08 +0100
Subject: Add working example of how to render a PDF to a PNG.

---
 doc/example.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 doc/example.c

(limited to 'doc')

diff --git a/doc/example.c b/doc/example.c
new file mode 100644
index 00000000..4467b32b
--- /dev/null
+++ b/doc/example.c
@@ -0,0 +1,100 @@
+// Rendering a page of a PDF document to a PNG image in less than 100 lines.
+
+// Compile a debug build of mupdf, then compile and run this example:
+//
+// gcc -o build/debug/example -I fitz doc/example.c \
+//	build/debug/libfitz.a build/debug/libfreetype.a -lpng -ljpeg \
+//	-ljbig2dec -lopenjpeg -lm
+//
+// build/debug/example /path/to/document.pdf 1 200 25
+
+// Include MuPDF header files. The order is important!
+
+#include <fitz.h>
+
+void
+render(char *filename, int pagenumber, int zoom, int rotation)
+{
+	// Create a context to hold the exception stack and various caches.
+
+	fz_context *ctx = fz_new_context(NULL, NULL, FZ_STORE_UNLIMITED);
+
+	// Open the PDF, XPS or CBZ document.
+
+	fz_document *doc = fz_open_document(ctx, filename);
+
+	// Retrieve the number of pages (not used in this example).
+
+	int pagecount = fz_count_pages(doc);
+
+	// Load the page we want. Page numbering starts from zero.
+
+	fz_page *page = fz_load_page(doc, pagenumber - 1);
+
+	// Calculate a transform to use when rendering. This transform
+	// contains the scale and rotation. Convert zoom percentage to a
+	// scaling factor. Without scaling the resolution is 72 dpi.
+
+	fz_matrix transform = fz_scale(zoom / 100.0f, zoom / 100.0f);
+	transform = fz_concat(transform, fz_rotate(rotation));
+
+	// Take the page bounds and transform them by the same matrix that
+	// we will use to render the page.
+
+	fz_rect rect = fz_bound_page(doc, page);
+	rect = fz_transform_rect(transform, rect);
+	fz_bbox bbox = fz_round_rect(rect);
+
+	// Create a blank pixmap to hold the result of rendering. The
+	// pixmap bounds used here are the same as the transformed page
+	// bounds, so it will contain the entire page. The page coordinate
+	// space has the origin at the top left corner and the x axis
+	// extends to the right and the y axis extends down.
+
+	fz_pixmap *pix = fz_new_pixmap_with_rect(ctx, fz_device_rgb, bbox);
+	fz_clear_pixmap_with_value(ctx, pix, 0xff);
+
+	// A page consists of a series of objects (text, line art, images,
+	// gradients). These objects are passed to a device when the
+	// interpreter runs the page. There are several devices, used for
+	// different purposes:
+	//
+	//	draw device -- renders objects to a target pixmap.
+	//
+	//	text device -- extracts the text in reading order with styling
+	//	information. This text can be used to provide text search.
+	//
+	//	list device -- records the graphic objects in a list that can
+	//	be played back through another device. This is useful if you
+	//	need to run the same page through multiple devices, without
+	//	the overhead of parsing the page each time.
+
+	// Create a draw device with the pixmap as its target.
+	// Run the page with the transform.
+
+	fz_device *dev = fz_new_draw_device(ctx, pix);
+	fz_run_page(doc, page, dev, transform, NULL);
+	fz_free_device(dev);
+
+	// Save the pixmap to a file.
+
+	fz_write_png(ctx, pix, "out.png", 0);
+
+	// Clean up.
+
+	fz_drop_pixmap(ctx, pix);
+	fz_free_page(doc, page);
+	fz_close_document(doc);
+	fz_free_context(ctx);
+}
+
+int main(int argc, char **argv)
+{
+	char *filename = argv[1];
+	int pagenumber = argc > 2 ? atoi(argv[2]) : 1;
+	int zoom = argc > 3 ? atoi(argv[3]) : 100;
+	int rotation = argc > 4 ? atoi(argv[4]) : 0;
+
+	render(filename, pagenumber, zoom, rotation);
+	return 0;
+}
-- 
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