[cairo-commit] [cairo-www] src/cookbook

[Carl Worth]

 src/cookbook/emboss.c.mdwn |  155 ---------------------------------------------
 1 file changed, 155 deletions(-)

New commits:
commit 53dd40edaaafd2e43b06f9ad083be380c054d0f7
Author: cubicool <cubicool at web>
Date:   Tue Oct 19 10:54:25 2010 -0700

diff --git a/src/cookbook/emboss.c.mdwn b/src/cookbook/emboss.c.mdwn
index bd0b858..8b13789 100644
--- a/src/cookbook/emboss.c.mdwn
+++ b/src/cookbook/emboss.c.mdwn
@@ -1,156 +1 @@
-/*
-Adapted from "Fast Embossing Effects on Raster Image Data"
-	
-	Original code by: John Schlag, <jfs at kerner.com>
-	Adapted code by: Jeremy Moles, <cubicool at gmail.com>
 
-Found in the publication "Graphics Gems IV", Academic Press, 1994
-*/
-
-
-#include <cairo.h>
-#include <math.h>
-#include <stdio.h>
-#include <string.h>
-#include <stdlib.h>
-
-#define PIXEL_SCALE 255
-#define WIDTH_45    1
-
-/* This function will use an exisiting surface's data and create and NEW surface copy
-// of that data which has the emboss lighting algorightm applied to it. */
-static cairo_surface_t* _create_embossed_surface_from_surface(
-	cairo_surface_t* surface,
-	double           azimuth,
-	double           elevation
-) {
-	unsigned char* src    = cairo_image_surface_get_data(surface);
-	unsigned int   width  = cairo_image_surface_get_width(surface);
-	unsigned int   stride = cairo_image_surface_get_stride(surface);
-	unsigned int   height = cairo_image_surface_get_height(surface);
-	
-	cairo_surface_t* dstSurface = cairo_image_surface_create(CAIRO_FORMAT_A8, width, height);
-
-	unsigned char* dst = cairo_image_surface_get_data(dstSurface);
-
-	/* Compute the light vector from the input parameters.
-	// Normalize the length to PIXEL_SCALE for fast shading calculation. */
-	long Lx   = cos(azimuth) * cos(elevation) * PIXEL_SCALE;
-	long Ly   = sin(azimuth) * cos(elevation) * PIXEL_SCALE;
-	long Lz   = sin(elevation) * PIXEL_SCALE;
-	long Nz   = (6 * 255) / WIDTH_45;
-	long Nz2  = Nz * Nz;
-	long NzLz = Nz * Lz;
-
-	unsigned int y = 1;
-	unsigned int x = 1;
-
-	/* TODO: Would it be better to fill DST with SRC instead of the Lz value?
-	// memcpy(dst, src, stride * height); */
-	memset(dst, Lz, stride * height);
-
-	for(y = 1; y < height - 2; y++) {
-		for(x = 1; x < stride - 1; x++) {
-			unsigned int   offset = (y * stride) + x;
-			unsigned char* s1     = src + offset;
-			unsigned char* s2     = s1 + stride;
-			unsigned char* s3     = s2 + stride;
-			unsigned char  shade  = 0;
-
-			/* Compute the normal from the source. The type of the expression
-			// before the cast is compiler dependent. In some cases the sum is
-			// unsigned, in others it is signed. Ergo, cast to signed. */
-			long Nx = (long)(s1[-1] + s2[-1] + s3[-1] - s1[1] - s2[1] - s3[1]);
-			long Ny = (long)(s3[-1] + s3[0] + s3[1] - s1[-1] - s1[0] - s1[1]);
-			
-			long NdotL = Nx * Lx + Ny * Ly + NzLz;
-
-			/* Shade with distant light source. */
-			if(!Nx && !Ny) shade = Lz;
-
-			else if(NdotL < 0) shade = 0;
-
-			else shade = NdotL / sqrt(Nx * Nx + Ny * Ny + Nz2);
-			
-			*(dst + offset) = shade;
-		}
-	}
-
-	return dstSurface;
-}
-
-/* This function only supports A8 surfaces at the moment, and delegates work to the
-// similarly named function above. */
-static cairo_surface_t* create_embossed_surface_from_surface(
-	cairo_surface_t* surface,
-	double           azimuth,
-	double           elevation
-) {
-	if(cairo_image_surface_get_format(surface) != CAIRO_FORMAT_A8) {
-		printf("This example only supports embossing A8 surfaces.\n");
-		printf("It shouldn't be too wildy hard to add other format types.\n");
-
-		return 0;
-	}
-
-	else return _create_embossed_surface_from_surface(surface, azimuth, elevation);
-}
-
-int main(int argc, char** argv) {
-	unsigned int w        = 400;
-	unsigned int h        = 50;
-	unsigned int textSize = 35;
-	const char*  text     = "Cairo Emboss!!!";
-
-	cairo_surface_t* surface = cairo_image_surface_create(CAIRO_FORMAT_A8, w, h);
-	cairo_t*         cr      = cairo_create(surface);
-
-	cairo_text_extents_t extents;
-
-	if(argc != 3) {
-		printf(
-			"usage: %s <int> <int>\nThe two integral arguments passed in are "
-			"the light azimuth and elevation values, in angles.\n",
-			argv[0]
-		);
-
-		goto cleanup;
-	}
-
-	cairo_select_font_face(cr, "Sans", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_BOLD);
-	cairo_set_font_size(cr, textSize);
-	cairo_text_extents(cr, text, &extents);
-
-	cairo_move_to(
-		cr,
-		((double)(w - extents.width) / 2.0f) - extents.x_bearing,
-		(double)(h - extents.y_bearing) / 2.0f
-	);
-
-	cairo_show_text(cr, text);
-
-	cairo_surface_t* emboss = create_embossed_surface_from_surface(
-		surface, 
-		atoi(argv[1]) * (M_PI / 180.0f),
-		atoi(argv[2]) * (M_PI / 180.0f)
-	);
-
-	if(!emboss) {
-		printf("Calling the emboss function failed; cleaning up and leaving.\n");
-
-		goto cleanup;
-	}
-
-	cairo_surface_write_to_png(surface, "cairo_emboss_normal.png");
-	cairo_surface_write_to_png(emboss, "cairo_emboss_embossed.png");
-
-	printf("Wrote cairo_emboss_{normal,embossed}.png to your local directory.\n");
-
-	cairo_surface_destroy(emboss);
-
-cleanup:
-	cairo_surface_destroy(surface);
-	cairo_destroy(cr);
-	
-	return 0;
-}