Upgrade the bundled nanosvg library to current version

For details see README.bundled-libs.txt.

README.bundled-libs.txt

@@ -20,12 +20,12 @@ Current versions of bundled libraries (as of Sep 13, 2021):
   Library       Version            Release date         FLTK Version
   --------------------------------------------------------------------------
   jpeg          jpeg-9d            2020-01-12           1.4.0
-  nanosvg       461ad7de70 [1]     2021-09-13           1.4.0
+  nanosvg       06a9113e29 [1]     2022-07-09           1.4.0
   png           libpng-1.6.37      2019-04-14           1.4.0
   zlib          zlib-1.2.11        2017-01-15           1.4.0
   --------------------------------------------------------------------------
 
-Previous versions of bundled libraries:
+Previous versions of bundled libraries (FLTK 1.3.x):
 
   Library       Version            Release date         FLTK Version
   ------------------------------------------------------------------
@@ -271,3 +271,68 @@ nanosvg:
 
     nanosvg.h:     Merge or download from FLTK's fork (see above).
     nanosvgrast.h: Merge or download from FLTK's fork (see above).
+
+  Maintaining branch 'fltk' in FLTK's fork of nanosvg (fltk/nanosvg):
+
+    Only maintainers with write access on fltk/nanosvg can do this.
+    Others can fork our fltk/nanosvg fork in their own GitHub account
+    and either open a PR on fltk/nanosvg or tell us about their
+    changes in fltk.development.
+
+    Use something similar to the following commands to update FLTK's
+    fork of nanosvg to the latest version. Commands are only examples,
+    you may need to change more or less, depending on the outstanding
+    updates.
+
+    Step 1: clone the fltk/nanosvg fork, set the remote 'upstream',
+    and update the 'master' branch:
+
+    $ cd /to/your/dev/dir
+    $ git clone https://github.com/fltk/nanosvg.git nanosvg-fltk
+    $ cd nanosvg-fltk
+    $ git remote add upstream https://github.com/memononen/nanosvg
+    $ git checkout master
+    $ git pull upstream master
+
+    Note: the 'master' branch must never be changed, i.e. it must
+    always be the same as 'upstream/master'. Never commit your own
+    (FLTK specific) changes to branch 'master'.
+
+    Step 2: rebase branch 'fltk' on the new master (upstream/master),
+    fix potential conflicts, and tag the new branch.
+
+    It is important to keep the individual FLTK specific patches intact
+    (one commit per patch) because this will preserve the history and
+    the committer and make it easier to skip single patches when they
+    are accepted upstream.
+
+    $ git checkout fltk
+    $ git rebase upstream/master
+
+    At this point you may need to fix conflicts! Do whatever is
+    necessary to update the branch 'fltk'.
+
+    Now `git tag' the 'fltk' branch for later reference.
+
+    Hint: use `git show <any-older-tag-name>' to see its contents.
+    I like to write a summary of commits in the tag comment.
+
+    $ git tag -a fltk_yyyy-mm-dd fltk
+
+    Replace 'yyyy-mm-dd' with the current date and add a comment
+    when asked for it (your editor will open an empty file).
+
+    Step 3: at this point it is recommended to copy the changed
+    header files to your working copy of the FLTK library and test
+    the changes. If anything is wrong, go back, fix the bugs
+    and change the git tag (delete and create a new one).
+
+    Step 4: push the new branch 'fltk' and the tag to the fltk/nanosvg
+    repository:
+
+    $ git push -f origin fltk
+    $ git push origin fltk_yyyy-mm-dd
+
+    Step 5: copy the changed files to your working copy of the FLTK
+    repository (if not done already), update this file accordingly,
+    and commit/push the update to the fltk/fltk repository.

nanosvg/nanosvg.h

@@ -181,12 +181,11 @@ void nsvgDelete(NSVGimage* image);
 #endif
 #endif
 
-#endif // NANOSVG_H
-
 #ifdef NANOSVG_IMPLEMENTATION
 
 #include <string.h>
 #include <stdlib.h>
+#include <stdio.h>
 #include <math.h>
 
 #define NSVG_PI (3.14159265358979323846264338327f)
@@ -1231,18 +1230,58 @@ static unsigned int nsvg__parseColorHex(const char* str)
 	return NSVG_RGB(128, 128, 128);
 }
 
+// Parse rgb color. The pointer 'str' must point at "rgb(" (4+ characters).
+// This function returns gray (rgb(128, 128, 128) == '#808080') on parse errors
+// for backwards compatibility. Note: other image viewers return black instead.
+
 static unsigned int nsvg__parseColorRGB(const char* str)
 {
-	unsigned int r=0, g=0, b=0;
+	int i;
-	if (sscanf(str, "rgb(%u, %u, %u)", &r, &g, &b) == 3)		// decimal integers
+	unsigned int rgbi[3];
-		return NSVG_RGB(r, g, b);
+	float rgbf[3];
-	if (sscanf(str, "rgb(%u%%, %u%%, %u%%)", &r, &g, &b) == 3) {	// decimal integer percentage
+	// try decimal integers first
-		r = (r <= 100) ? ((r*255)/100) : 255;			// FLTK: clip percentages >100
+	if (sscanf(str, "rgb(%u, %u, %u)", &rgbi[0], &rgbi[1], &rgbi[2]) != 3) {
-		g = (g <= 100) ? ((g*255)/100) : 255;
+		// integers failed, try percent values (float, locale independent)
-		b = (b <= 100) ? ((b*255)/100) : 255;
+		const char delimiter[3] = {',', ',', ')'};
-		return NSVG_RGB(r, g, b);
+		str += 4; // skip "rgb("
+		for (i = 0; i < 3; i++) {
+			while (*str && (nsvg__isspace(*str))) str++; 	// skip leading spaces
+			if (*str == '+') str++;				// skip '+' (don't allow '-')
+			if (!*str) break;
+			rgbf[i] = nsvg__atof(str);
+
+			// Note 1: it would be great if nsvg__atof() returned how many
+			// bytes it consumed but it doesn't. We need to skip the number,
+			// the '%' character, spaces, and the delimiter ',' or ')'.
+
+			// Note 2: The following code does not allow values like "33.%",
+			// i.e. a decimal point w/o fractional part, but this is consistent
+			// with other image viewers, e.g. firefox, chrome, eog, gimp.
+
+			while (*str && nsvg__isdigit(*str)) str++;		// skip integer part
+			if (*str == '.') {
+				str++;
+				if (!nsvg__isdigit(*str)) break;		// error: no digit after '.'
+				while (*str && nsvg__isdigit(*str)) str++;	// skip fractional part
 			}
-	return NSVG_RGB(128, 128, 128);
+			if (*str == '%') str++; else break;
+			while (nsvg__isspace(*str)) str++;
+			if (*str == delimiter[i]) str++;
+			else break;
+		}
+		if (i == 3) {
+			rgbi[0] = roundf(rgbf[0] * 2.55f);
+			rgbi[1] = roundf(rgbf[1] * 2.55f);
+			rgbi[2] = roundf(rgbf[2] * 2.55f);
+		} else {
+			rgbi[0] = rgbi[1] = rgbi[2] = 128;
+		}
+	}
+	// clip values as the CSS spec requires
+	for (i = 0; i < 3; i++) {
+		if (rgbi[i] > 255) rgbi[i] = 255;
+	}
+	return NSVG_RGB(rgbi[0], rgbi[1], rgbi[2]);
 }
 
 typedef struct NSVGNamedColor {
@@ -3017,4 +3056,6 @@ void nsvgDelete(NSVGimage* image)
 	free(image);
 }
 
-#endif
+#endif // NANOSVG_IMPLEMENTATION
+
+#endif // NANOSVG_H

nanosvg/nanosvgrast.h

@@ -31,6 +31,8 @@
 #ifndef NANOSVGRAST_H
 #define NANOSVGRAST_H
 
+#include "nanosvg.h"
+
 #ifndef NANOSVGRAST_CPLUSPLUS
 #ifdef __cplusplus
 extern "C" {
@@ -87,11 +89,11 @@ void nsvgDeleteRasterizer(NSVGrasterizer*);
 #endif
 #endif
 
-#endif // NANOSVGRAST_H
-
 #ifdef NANOSVGRAST_IMPLEMENTATION
 
 #include <math.h>
+#include <stdlib.h>
+#include <string.h>
 
 #define NSVG__SUBSAMPLES	5
 #define NSVG__FIXSHIFT		10
@@ -972,7 +974,7 @@ static float nsvg__clampf(float a, float mn, float mx) { return a < mn ? mn : (a
 
 static unsigned int nsvg__RGBA(unsigned char r, unsigned char g, unsigned char b, unsigned char a)
 {
-	return (r) | (g << 8) | (b << 16) | (a << 24);
+	return ((unsigned int)r) | ((unsigned int)g << 8) | ((unsigned int)b << 16) | ((unsigned int)a << 24);
 }
 
 static unsigned int nsvg__lerpRGBA(unsigned int c0, unsigned int c1, float u)
@@ -1423,6 +1425,7 @@ void nsvgRasterizeXY(NSVGrasterizer* r,
 			}
 
 			// Rasterize edges
+			if (r->nedges != 0)
 				qsort(r->edges, r->nedges, sizeof(NSVGedge), nsvg__cmpEdge);
 
 			// now, traverse the scanlines and find the intersections on each scanline, use non-zero rule
@@ -1449,6 +1452,7 @@ void nsvgRasterizeXY(NSVGrasterizer* r,
 			}
 
 			// Rasterize edges
+			if (r->nedges != 0)
 				qsort(r->edges, r->nedges, sizeof(NSVGedge), nsvg__cmpEdge);
 
 			// now, traverse the scanlines and find the intersections on each scanline, use non-zero rule
@@ -1474,3 +1478,5 @@ void nsvgRasterize(NSVGrasterizer* r,
 }
 
 #endif // NANOSVGRAST_IMPLEMENTATION
+
+#endif // NANOSVGRAST_H