X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/rigol/blobdiff_plain/3df147113765d5a8ba192795d2be9b7e3e295749..7df76f49adf30ac260c99649678b084c9b6c282b:/png.c

diff --git a/png.c b/png.c
index 98d5993..ac09767 100644
--- a/png.c
+++ b/png.c
@@ -2,9 +2,15 @@
 #include <stdint.h>
 #include <arpa/inet.h>
 #include <zlib.h>
+#include <stdio.h>
+#include <stdlib.h>
 
 #include "png.h"
 
+#define CHUNK 16384
+#define WIDTH 320
+#define HEIGHT 234
+
 /* Table of CRCs of all 8-bit messages. */
 static unsigned long crc_table[256];
 
@@ -57,25 +63,31 @@ static unsigned long crc(unsigned char *buf, int len)
 
 unsigned char *lcd2png(unsigned char *lcd, int *len)
 {
-	unsigned char screen_conv[320*234*3];
+	unsigned char screen_conv[(WIDTH*HEIGHT*3)+HEIGHT]; /* 320*234 RGB + scanline filter byte */
+	unsigned char *pos;
 	unsigned char lut[256][3];
-	unsigned char *image;
+	unsigned char *screen_deflated;
+	int deflated_size;
+	unsigned char *image = NULL;
 	unsigned char *outpos;
 	static const unsigned char png[] = {137, 80, 78, 71, 13, 10, 26, 10};
+	static unsigned char idat[] = {'I', 'D', 'A', 'T'};
+	static unsigned char iend[] = {'I', 'E', 'N', 'D'};
 	static unsigned char ihdr[] = {'I', 'H', 'D', 'R',
 		0x00, 0x00, 0x01, 0x40, /* 320 - Width */
 		0x00, 0x00, 0x00, 0xea, /* 234 - Height */
 		0x08, /* Bit depth */
 		0x02, /* RGB Truecolor, Colour type */
 		0x00, /* Deflate, Compression method */
-		0x00, /* None, Filter method */
+		0x00, /* Adaptive, Filter method */
 		0x00  /* No interlace, Interlace method */
 		};
-	static unsigned char idat[] = {'I', 'D', 'A', 'T'};
-	static unsigned char iend[] = {'I', 'E', 'N', 'D'};
 	uint32_t l;
 	int i;
+	int ret;
 	int toalloc = 0;
+	int flush;
+	z_stream strm;
 
 	for(i = 0; i < 256; i++) {
 		lut[i][0] = ((i >> 6) * 0x55);
@@ -83,32 +95,105 @@ unsigned char *lcd2png(unsigned char *lcd, int *len)
 		lut[i][2] = (((i & 7) * 0x49) >> 1);
 	}
 
-	for(i = 0; i < sizeof(screen_conv); i += 3) {
-		screen_conv[i] = lut[lcd[i/3]][0];
-		screen_conv[i+1] = lut[lcd[i/3]][1];
-		screen_conv[i+2] = lut[lcd[i/3]][2];
+	pos = screen_conv;
+	for(i = 0; i < (WIDTH*HEIGHT); i++) {
+		if ((i % WIDTH) == 0) {
+			*pos++ = 0x00; /* No adaptive filter */
+		}
+		*pos++ = lut[lcd[i]][0];
+		*pos++ = lut[lcd[i]][1];
+		*pos++ = lut[lcd[i]][2];
+	}
+
+	strm.zalloc = Z_NULL;
+	strm.zfree = Z_NULL;
+	strm.opaque = Z_NULL;
+	if (deflateInit(&strm, Z_BEST_COMPRESSION) != Z_OK) {
+		perror("deflateInit");
+		exit(EXIT_FAILURE);
 	}
 
-	image = malloc(320*234*2); /* TODO: FIXME! */
+	strm.avail_in = sizeof(screen_conv);
+	strm.next_in = screen_conv;
+
+	toalloc = 0;
+	strm.avail_out = 0;
+	screen_deflated = NULL;
+	flush = Z_NO_FLUSH;
+
+	do {
+		if (strm.avail_out == 0) {
+			toalloc += CHUNK;
+			screen_deflated = realloc(screen_deflated, toalloc);
+			if (screen_deflated == NULL) {
+				perror("realloc");
+				exit(EXIT_FAILURE);
+			}
+
+			strm.avail_out = CHUNK;
+			strm.next_out = screen_deflated + (toalloc - CHUNK);
+		}
+
+		ret = deflate(&strm, flush);
+		if (ret == Z_STREAM_ERROR) {
+			perror("deflate");
+			exit(EXIT_FAILURE);
+		}
+
+		if(strm.avail_in == 0) {
+			flush = Z_FINISH;
+		}
+	} while(ret != Z_STREAM_END);
+	deflated_size = toalloc - strm.avail_out;
+
+	deflateEnd(&strm);
+
+	image = malloc(sizeof(png) +
+		sizeof(ihdr) + 8 + /* 8 = length, csum */
+		sizeof(idat) + deflated_size + 8 +
+		sizeof(iend) + 8);
+	
+	if (image == NULL) {
+		perror("malloc");
+		return NULL;
+	}
+	
 	outpos = image;
+
+	/* PNG signature */
 	memcpy(outpos, png, sizeof(png));
 	outpos += sizeof(png);
 
+	/* IHDR */
 	l = htonl(sizeof(ihdr) - 4); /* "IHDR" is not counted */
 	memcpy(outpos, &l, sizeof(l));
 	outpos += sizeof(l);
 	memcpy(outpos, ihdr, sizeof(ihdr));
 	outpos += sizeof(ihdr);
-	l = crc(ihdr, sizeof(ihdr));
+	l = htonl(crc(ihdr, sizeof(ihdr)));
+	memcpy(outpos, &l, sizeof(l));
+	outpos += sizeof(l);
+
+	/* IDAT */
+	l = htonl(deflated_size);
+	memcpy(outpos, &l, sizeof(l));
+	outpos += sizeof(l);
+	memcpy(outpos, idat, sizeof(idat));
+	outpos += sizeof(idat);
+	memcpy(outpos, screen_deflated, deflated_size);
+	free(screen_deflated);
+	outpos +=deflated_size;
+	l = htonl(crc(outpos-deflated_size-sizeof(idat), deflated_size+sizeof(idat)));
 	memcpy(outpos, &l, sizeof(l));
 	outpos += sizeof(l);
 
+	/* IEND */
 	l = htonl(sizeof(iend) - 4); /* "IEND" is not counted */
 	memcpy(outpos, &l, sizeof(l));
 	outpos += sizeof(l);
 	memcpy(outpos, iend, sizeof(iend));
 	outpos += sizeof(iend);
-	l = crc(iend, sizeof(iend));
+	l = htonl(crc(iend, sizeof(iend)));
 	memcpy(outpos, &l, sizeof(l));
 	outpos += sizeof(l);