Add pixmap writing functions for PNM, PAM and PNG (without libpng) formats.

1 files changed, 183 insertions, 86 deletions

diff --git a/fitz/res_pixmap.c b/fitz/res_pixmap.c
index c6a299f9..ed596d7b 100644
--- a/fitz/res_pixmap.c
+++ b/fitz/res_pixmap.c
@@ -72,116 +72,213 @@ fz_gammapixmap(fz_pixmap *pix, float gamma)
 	}
 }
 
-void
-fz_debugpixmap(fz_pixmap *pix, char *prefix)
+/*
+ * Write pixmap to PNM file (without alpha channel)
+ */
+
+fz_error
+fz_writepnm(fz_pixmap *pixmap, char *filename)
 {
-	static int counter = 0;
-	char colorname[40];
-	char alphaname[40];
-	FILE *color = NULL;
-	FILE *alpha = NULL;
-	int x, y;
+	FILE *fp;
+	unsigned char *p;
+	int len;
 
-	sprintf(alphaname, "%s-%04d-alpha.pgm", prefix, counter);
-	alpha = fopen(alphaname, "wb");
-	if (!alpha)
-		goto cleanup;
+	if (pixmap->n != 1 && pixmap->n != 2 && pixmap->n != 4)
+		return fz_throw("pixmap must be grayscale or rgb to write as pnm");
 
-	fprintf(stderr, "saving debug pixmap %s-%04d (%s)\n", prefix, counter, pix->colorspace->name);
+	fp = fopen(filename, "wb");
+	if (!fp)
+		return fz_throw("cannot open file '%s': %s", filename, strerror(errno));
 
-	if (pix->n > 1)
-	{
-		if (pix->n > 2)
-			sprintf(colorname, "%s-%04d-color.ppm", prefix, counter);
-		else
-			sprintf(colorname, "%s-%04d-color.pgm", prefix, counter);
-
-		color = fopen(colorname, "wb");
-		if (!color)
-			goto cleanup;
-	}
+	if (pixmap->n == 1 || pixmap->n == 2)
+		fprintf(fp, "P5\n");
+	if (pixmap->n == 4)
+		fprintf(fp, "P6\n");
+	fprintf(fp, "%d %d\n", pixmap->w, pixmap->h);
+	fprintf(fp, "255\n");
 
-	counter ++;
+	len = pixmap->w * pixmap->h;
+	p = pixmap->samples;
 
-	if (pix->n == 5)
+	switch (pixmap->n)
 	{
-		fprintf(alpha, "P5\n%d %d\n255\n", pix->w, pix->h);
-		fprintf(color, "P6\n%d %d\n255\n", pix->w, pix->h);
-
-		for (y = 0; y < pix->h; y++)
+	case 1:
+		fwrite(p, 1, len, fp);
+		break;
+	case 2:
+		while (len--)
 		{
-			for (x = 0; x < pix->w; x++)
-			{
-				int cc = pix->samples[x * pix->n + y * pix->w * pix->n + 0];
-				int mm = pix->samples[x * pix->n + y * pix->w * pix->n + 1];
-				int yy = pix->samples[x * pix->n + y * pix->w * pix->n + 2];
-				int kk = pix->samples[x * pix->n + y * pix->w * pix->n + 3];
-				int a = pix->samples[x * pix->n + y * pix->w * pix->n + 4];
-				int r = 255 - MIN(cc + kk, 255);
-				int g = 255 - MIN(mm + kk, 255);
-				int b = 255 - MIN(yy + kk, 255);
-				fputc(a, alpha);
-				fputc(r, color);
-				fputc(g, color);
-				fputc(b, color);
-			}
+			putc(p[0], fp);
+			p += 2;
+		}
+		break;
+	case 4:
+		while (len--)
+		{
+			putc(p[0], fp);
+			putc(p[1], fp);
+			putc(p[2], fp);
+			p += 4;
 		}
 	}
 
-	else if (pix->n == 4)
-	{
-		fprintf(alpha, "P5\n%d %d\n255\n", pix->w, pix->h);
-		fprintf(color, "P6\n%d %d\n255\n", pix->w, pix->h);
+	fclose(fp);
+	return fz_okay;
+}
 
-		for (y = 0; y < pix->h; y++)
-		{
-			for (x = 0; x < pix->w; x++)
-			{
-				int r = pix->samples[x * pix->n + y * pix->w * pix->n + 0];
-				int g = pix->samples[x * pix->n + y * pix->w * pix->n + 1];
-				int b = pix->samples[x * pix->n + y * pix->w * pix->n + 2];
-				int a = pix->samples[x * pix->n + y * pix->w * pix->n + 3];
-				fputc(a, alpha);
-				fputc(r, color);
-				fputc(g, color);
-				fputc(b, color);
-			}
-		}
+/*
+ * Write pixmap to PAM file (with alpha channel)
+ */
+
+fz_error
+fz_writepam(fz_pixmap *pixmap, char *filename)
+{
+	FILE *fp;
+
+	fp = fopen(filename, "wb");
+	if (!fp)
+		return fz_throw("cannot open file '%s': %s", filename, strerror(errno));
+
+	fprintf(fp, "P7\n");
+	fprintf(fp, "WIDTH %d\n", pixmap->w);
+	fprintf(fp, "HEGIHT %d\n", pixmap->h);
+	fprintf(fp, "DEPTH %d\n", pixmap->n);
+	fprintf(fp, "MAXVAL 255\n");
+	switch (pixmap->n)
+	{
+	case 1: fprintf(fp, "TUPLTYPE GRAYSCALE\n"); break;
+	case 2: fprintf(fp, "TUPLTYPE GRAYSCALE_ALPHA\n"); break;
+	case 4: fprintf(fp, "TUPLTYPE RGB_ALPHA\n"); break;
+	case 5: fprintf(fp, "TUPLTYPE CMYK_ALPHA\n"); break;
 	}
+	fprintf(fp, "ENDHDR\n");
+
+	fwrite(pixmap->samples, pixmap->w * pixmap->n, pixmap->h, fp);
+
+	fclose(fp);
+
+	return fz_okay;
+}
+
+/*
+ * Write pixmap to PNG file (with or without alpha channel)
+ */
+
+#include <zlib.h>
 
-	else if (pix->n == 2)
+static inline void big32(unsigned char *buf, unsigned int v)
+{
+	buf[0] = (v >> 24) & 0xff;
+	buf[1] = (v >> 16) & 0xff;
+	buf[2] = (v >> 8) & 0xff;
+	buf[3] = (v) & 0xff;
+}
+
+static inline void put32(unsigned int v, FILE *fp)
+{
+	putc(v >> 24, fp);
+	putc(v >> 16, fp);
+	putc(v >> 8, fp);
+	putc(v, fp);
+}
+
+static void putchunk(char *tag, unsigned char *data, int size, FILE *fp)
+{
+	unsigned int sum;
+	put32(size, fp);
+	fwrite(tag, 1, 4, fp);
+	fwrite(data, 1, size, fp);
+	sum = crc32(0, NULL, 0);
+	sum = crc32(sum, (unsigned char*)tag, 4);
+	sum = crc32(sum, data, size);
+	put32(sum, fp);
+}
+
+fz_error
+fz_writepng(fz_pixmap *pixmap, char *filename, int alpha)
+{
+	static const unsigned char pngsig[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
+	FILE *fp;
+	unsigned char head[13];
+	unsigned char *udata, *cdata, *sp, *dp;
+	uLong usize, csize;
+	int y, x, k, sn, dn;
+	int color;
+	int err;
+
+	if (pixmap->n != 1 && pixmap->n != 2 && pixmap->n != 4)
+		return fz_throw("pixmap must be grayscale or rgb to write as png");
+
+	sn = pixmap->n;
+	dn = pixmap->n;
+	if (!alpha && dn > 1)
+		dn--;
+
+	switch (dn)
 	{
-		fprintf(alpha, "P5\n%d %d\n255\n", pix->w, pix->h);
-		fprintf(color, "P5\n%d %d\n255\n", pix->w, pix->h);
+	default:
+	case 1: color = 0; break;
+	case 2: color = 4; break;
+	case 3: color = 2; break;
+	case 4: color = 6; break;
+	}
+
+	usize = (pixmap->w * dn + 1) * pixmap->h;
+	csize = compressBound(usize);
+	udata = fz_malloc(usize);
+	cdata = fz_malloc(csize);
 
-		for (y = 0; y < pix->h; y++)
+	sp = pixmap->samples;
+	dp = udata;
+	for (y = 0; y < pixmap->h; y++)
+	{
+		*dp++ = 1; /* sub prediction filter */
+		for (x = 0; x < pixmap->w; x++)
 		{
-			for (x = 0; x < pix->w; x++)
+			for (k = 0; k < dn; k++)
 			{
-				int g = pix->samples[x * pix->n + y * pix->w * pix->n + 0];
-				int a = pix->samples[x * pix->n + y * pix->w * pix->n + 1];
-				fputc(a, alpha);
-				fputc(g, color);
+				if (x == 0)
+					dp[k] = sp[k];
+				else
+					dp[k] = sp[k] - sp[k-sn];
 			}
+			sp += sn;
+			dp += dn;
 		}
 	}
 
-	else if (pix->n == 1)
+	err = compress(cdata, &csize, udata, usize);
+	if (err != Z_OK)
 	{
-		fprintf(alpha, "P5\n%d %d\n255\n", pix->w, pix->h);
+		fz_free(udata);
+		fz_free(cdata);
+		return fz_throw("cannot compress image data");
+	}
 
-		for (y = 0; y < pix->h; y++)
-		{
-			for (x = 0; x < pix->w; x++)
-			{
-				int g = pix->samples[x * pix->n + y * pix->w * pix->n + 0];
-				fputc(g, alpha);
-			}
-		}
+
+	fp = fopen(filename, "wb");
+	if (!fp)
+	{
+		fz_free(udata);
+		fz_free(cdata);
+		return fz_throw("cannot open file '%s': %s", filename, strerror(errno));
 	}
 
-cleanup:
-	if (alpha) fclose(alpha);
-	if (color) fclose(color);
-}
+	big32(head+0, pixmap->w);
+	big32(head+4, pixmap->h);
+	head[8] = 8; /* depth */
+	head[9] = color;
+	head[10] = 0; /* compression */
+	head[11] = 0; /* filter */
+	head[12] = 0; /* interlace */
+
+	fwrite(pngsig, 1, 8, fp);
+	putchunk("IHDR", head, 13, fp);
+	putchunk("IDAT", cdata, csize, fp);
+	putchunk("IEND", head, 0, fp);
+	fclose(fp);
 
+	fz_free(udata);
+	fz_free(cdata);
+	return fz_okay;
+}