reading PNG with pnglite is wtf

.gitignore

@@ -32,6 +32,7 @@ funcs/V/*
 funcs/*.gif
 funcs/*.fits
 funcs/*.tiff
+funcs/toto
 
 scripts/*.fimg
 scripts/*.pnm

funcs/README.md

@@ -2,6 +2,12 @@
 
 Plein de fonctions qu'il serait bon de documenter :)
 
+## PNG
+
+__Attention__ : la bibliothèque `pnglite`actuellement utiilsée pour lire les
+fichiers PNG n'accepte que **certains** types de fichiers.
+Et en particulier, elle brotche sur ceux produits par ImageMagick !
+
 ## Contours
 
 Détecter des contours est une activité respectable.

funcs/fimg-png.c

@@ -1,6 +1,6 @@
 /*
  *		Lecture des images PNG
- *		L'ecriture est en chantier :}
+ *		----------------------
  */
 
 #include <stdio.h>
@@ -13,29 +13,14 @@
 
 extern int		verbosity;
 
-/* --------------------------------------------------------------------- */
-static char *pngerr2str(int code)
-{
-switch (code)	{
-	case	1:			return "Done";
-	case	0:			return "No error";
-	case	-1:			return "File error";
-	case	-2:			return "Header error";
-	case	-3:			return "IO error";
-	case	-4:			return "EOF error";
-	case	-5:			return "CRC error";
-	case	-6:			return "Memory error";
-	case	-7:			return "Zlib error";
-	case	-8:			return "Unknow filter";
-	case	-9:			return "Not supported";
-	case	-10:			return "Wrong arguments";
-	}
-return "*unknow*";
-}
 /* --------------------------------------------------------------------- */
 /*
  *	warning : this func has been tested only with
  * 	RGB (3x8bits) PNG files
+ *
+ * 	Attention : certains fichiers, tels que ceux
+ * 	produits par ImageMagick ne sont pas lisibles
+ * 	par cette fonction :(
  */
 int fimg_create_from_png(char *filename, FloatImg *fimg)
 {
@@ -57,31 +42,27 @@ png_init(NULL, NULL);			/* this is VITAL ! */
 foo = png_open_file_read(&png, filename);
 if (PNG_NO_ERROR != foo) {
 	fprintf(stderr, "%s :\n\topen_file '%s' = %d %s\n", __func__,
-			filename, foo, pngerr2str(foo));
+			filename, foo, png_error_string(foo));
+	png_close_file(&png);
 	return foo;
 	}
 #if DEBUG_LEVEL > 1
 fprintf(stderr, "%s opened\n", filename);
 #endif
 
-datasize = png.width * png.height * png.bpp;
+if (verbosity) {
+	printf("----------- %s ---------\n", filename);
+	png_print_info(&png);		puts("");
+	fflush(stdout);
+	}
 
 if ( 3 != png.bpp ) {
-	/* I don't really understand this part of the code */
 	fprintf(stderr, "bpp format %d of '%s' not supported\n",
 			png.color_type, filename);
 	return -21;
 	}
 
-#if DEBUG_LEVEL
+datasize = png.width * png.height * png.bpp;
-printf("\t%s is %d x %d\n", filename, png.width, png.height);
-printf("\tdatalen       %d\n", png.png_datalen);
-printf("\tcolor type    %d\n", png.color_type);
-printf("\tbyte/pixel    %d\n", png.bpp);
-printf("\tdatasize      %d\n", datasize);
-puts(""); png_print_info(&png); puts("");
-#endif
-
 datas = malloc(datasize);
 if (NULL==datas) {
 	fprintf(stderr, "%s : fatal memory failure\n", __func__);
@@ -95,10 +76,12 @@ if (foo) {
 	exit(1);
 	}
 
+/* I GET AN 'Unknown file error' HERE, WHY ???*/
 foo = png_get_data(&png, datas);
 if (PNG_NO_ERROR != foo) {
-	fprintf(stderr, "error in '%s' :\n\tpng_get_data -> %d = %s\n",
+	fprintf(stderr, "err in '%s:%s' :\n\tpng_get_data -> %d = %s\n\n",
-			__func__, foo, pngerr2str(foo));
+			__FILE__, __func__, foo, png_error_string(foo));
+	png_close_file(&png);
 	return foo;
 	}
 

funcs/t.c

@@ -1,4 +1,5 @@
 /*
+ *	tests des fonctions diverses
  */
 
 #include <stdio.h>
@@ -6,7 +7,8 @@
 #include <string.h>
 #include  <pam.h>
 
-
+#undef 		DEBUG_LEVEL
+#define		DEBUG_LEVEL	1
 
 #include "../floatimg.h"
 
@@ -48,6 +50,8 @@ return 0;
 /* --------------------------------------------------------------------- */
 /*
  *	nouveau 7 octobre 2020 pendant sonoptic
+ *
+ *	inspiration:  Olivier Baudu
  */
 
 int essai_qsort_rgb(char *infile, char *outfile)
@@ -314,10 +318,8 @@ if (foo) {
 	return -44;
 	}
 
-
 fimg_filter_3x3(&src, &dst, &filter_a);
 
-
 foo = fimg_clamp_negativ(&dst);
 
 if (foo) {
@@ -539,6 +541,30 @@ fprintf(stderr, "make h deg -> %d\n", foo);
 foo = fimg_save_as_pnm(&fimg, "vdeg.pnm", 0);
 fprintf(stderr, "%s: save as pnm -> %d\n", __func__, foo);
 
+return 0;
+}
+/* --------------------------------------------------------------------- */
+int essai_lecture_png(char *fname, char *outfile, int notused)
+{
+FloatImg	fimg;
+int		foo;
+
+fprintf(stderr, ">>> %s ( '%s' %d  )\n", __func__, fname, notused);
+
+memset(&fimg, 0, sizeof(FloatImg));
+foo = fimg_create_from_png(fname, &fimg);
+if (foo) {
+	fprintf(stderr, "%s: createfrom -> %d\n", __func__, foo);
+	return foo;
+	}
+fimg_describe(&fimg, "created from png");
+
+foo = fimg_export_picture(&fimg, outfile, 0);
+if (foo) {
+	fprintf(stderr, "%s : err %d saving result to %s\n", __func__,
+				foo, outfile);
+	return foo;
+	}
 return 0;
 }
 /* --------------------------------------------------------------------- */
@@ -595,7 +621,7 @@ return 0;
 /* --------------------------------------------------------------------- */
 enum nCmd { Equalize=1, Rotate, Sfx0, F3x3, MIRE, Wfits, Wpng, Wtiff,
 			Histo, Hsv, Classif, Ctr2x2, Qsortrgb,
-			Displace  };
+			Displace, ReadPNG  };
 typedef struct {
 	char	*name;
 	int	Cmd;
@@ -616,6 +642,7 @@ Command commands[] = {
 	{ "ctr2x2",	Ctr2x2		},
 	{ "qsortrgb",	Qsortrgb	},
 	{ "displace",	Displace	},
+	{ "readpng",	ReadPNG		},
 	{ NULL,		0		}
 	} ;
 
@@ -733,6 +760,9 @@ switch(opt) {
 	case Displace:
 		foo = essai_displacement(filename, outfile);
 		break;
+	case ReadPNG:
+		foo = essai_lecture_png(filename, outfile, 0);
+		break;
 	default:
 		fprintf(stderr, "%s : bad command\n", command);
 		exit(1);