Implement request #33066: Add GD Image Function gdImageOpenPolygon()

gdImageOpenPolygon() has been introduced with líbgd 2.0.29, so we finally
add a PHP binding for it, and port the respective libgd functionality to
PHP's bundled libgd.

ext/gd/gd.c

@@ -578,6 +578,13 @@ ZEND_BEGIN_ARG_INFO(arginfo_imagepolygon, 0)
 	ZEND_ARG_INFO(0, col)
 ZEND_END_ARG_INFO()
 
+ZEND_BEGIN_ARG_INFO(arginfo_imageopenpolygon, 0)
+	ZEND_ARG_INFO(0, im)
+	ZEND_ARG_INFO(0, points) /* ARRAY_INFO(0, points, 0) */
+	ZEND_ARG_INFO(0, num_pos)
+	ZEND_ARG_INFO(0, col)
+ZEND_END_ARG_INFO()
+
 ZEND_BEGIN_ARG_INFO(arginfo_imagefilledpolygon, 0)
 	ZEND_ARG_INFO(0, im)
 	ZEND_ARG_INFO(0, points) /* ARRAY_INFO(0, points, 0) */
@@ -938,6 +945,7 @@ const zend_function_entry gd_functions[] = {
 	PHP_FE(imageline,								arginfo_imageline)
 	PHP_FE(imageloadfont,							arginfo_imageloadfont)
 	PHP_FE(imagepolygon,							arginfo_imagepolygon)
+	PHP_FE(imageopenpolygon,						arginfo_imageopenpolygon)
 	PHP_FE(imagerectangle,							arginfo_imagerectangle)
 	PHP_FE(imagesetpixel,							arginfo_imagesetpixel)
 	PHP_FE(imagestring,								arginfo_imagestring)
@@ -3346,6 +3354,7 @@ PHP_FUNCTION(imageinterlace)
 /* }}} */
 
 /* {{{ php_imagepolygon
+   arg = -1 open polygon
    arg = 0  normal polygon
    arg = 1  filled polygon */
 /* im, points, num_points, col */
@@ -3398,10 +3407,16 @@ static void php_imagepolygon(INTERNAL_FUNCTION_PARAMETERS, int filled)
 		gdImageSetAntiAliased(im, col);
 		col = gdAntiAliased;
 	}
-	if (filled) {
+	switch (filled) {
-		gdImageFilledPolygon(im, points, npoints, col);
+		case -1:
-	} else {
+			gdImageOpenPolygon(im, points, npoints, col);
-		gdImagePolygon(im, points, npoints, col);
+			break;
+		case 0:
+			gdImagePolygon(im, points, npoints, col);
+			break;
+		case 1:
+			gdImageFilledPolygon(im, points, npoints, col);
+			break;
 	}
 
 	efree(points);
@@ -3417,6 +3432,14 @@ PHP_FUNCTION(imagepolygon)
 }
 /* }}} */
 
+/* {{{ proto bool imageopenpolygon(resource im, array point, int num_points, int col)
+   Draw a polygon */
+PHP_FUNCTION(imageopenpolygon)
+{
+	php_imagepolygon(INTERNAL_FUNCTION_PARAM_PASSTHRU, -1);
+}
+/* }}} */
+
 /* {{{ proto bool imagefilledpolygon(resource im, array point, int num_points, int col)
    Draw a filled polygon */
 PHP_FUNCTION(imagefilledpolygon)

ext/gd/libgd/gd.c

@@ -2605,6 +2605,17 @@ void gdImageCopyResampled (gdImagePtr dst, gdImagePtr src, int dstX, int dstY, i
 }
 
 void gdImagePolygon (gdImagePtr im, gdPointPtr p, int n, int c)
+{
+	if (n <= 0) {
+		return;
+	}
+
+
+	gdImageLine (im, p->x, p->y, p[n - 1].x, p[n - 1].y, c);
+	gdImageOpenPolygon (im, p, n, c);
+}
+
+void gdImageOpenPolygon (gdImagePtr im, gdPointPtr p, int n, int c)
 {
 	int i;
 	int lx, ly;
@@ -2615,7 +2626,6 @@ void gdImagePolygon (gdImagePtr im, gdPointPtr p, int n, int c)
 
 	lx = p->x;
 	ly = p->y;
-	gdImageLine(im, lx, ly, p[n - 1].x, p[n - 1].y, c);
 	for (i = 1; i < n; i++) {
 		p++;
 		gdImageLine(im, lx, ly, p->x, p->y, c);

ext/gd/libgd/gd.h

@@ -493,6 +493,7 @@ typedef struct {
 } gdPoint, *gdPointPtr;
 
 void gdImagePolygon(gdImagePtr im, gdPointPtr p, int n, int c);
+void gdImageOpenPolygon(gdImagePtr im, gdPointPtr p, int n, int c);
 void gdImageFilledPolygon(gdImagePtr im, gdPointPtr p, int n, int c);
 
 /* These functions still work with truecolor images,

ext/gd/php_gd.h

@@ -174,6 +174,7 @@ PHP_FUNCTION(imageinterlace);
 PHP_FUNCTION(imageline);
 PHP_FUNCTION(imageloadfont);
 PHP_FUNCTION(imagepolygon);
+PHP_FUNCTION(imageopenpolygon);
 PHP_FUNCTION(imagerectangle);
 PHP_FUNCTION(imagesetpixel);
 PHP_FUNCTION(imagestring);

ext/gd/tests/imageopenpolygon_basic.phpt

@@ -0,0 +1,29 @@
+--TEST--
+imageopenpolygon(): basic test
+--SKIPIF--
+<?php
+if (!extension_loaded('gd')) die('skip gd extension not available');
+?>
+--FILE--
+<?php
+require_once __DIR__ . DIRECTORY_SEPARATOR . 'func.inc';
+
+$im = imagecreatetruecolor(100, 100);
+$white = imagecolorallocate($im, 255, 255, 255);
+$black = imagecolorallocate($im, 0, 0, 0);
+$red = imagecolorallocate($im, 255, 0, 0);
+$green = imagecolorallocate($im, 0, 128, 0);
+$blue = imagecolorallocate($im, 0, 0, 255);
+imagefilledrectangle($im, 0,0, 99,99, $white);
+
+imageopenpolygon($im, [10,10, 49,89, 89,10], 3, $black);
+imageopenpolygon($im, [10,89, 35,10, 60,89, 85,10], 4, $red);
+imageopenpolygon($im, [10,49, 30,89, 50,10, 70,89, 90,10], 5, $green);
+imageopenpolygon($im, [10,50, 25,10, 40,89, 55,10, 80,89, 90,50], 6, $blue);
+
+test_image_equals_file(__DIR__ . DIRECTORY_SEPARATOR . 'imageopenpolygon.png', $im);
+?>
+===DONE===
+--EXPECT--
+The images are equal.
+===DONE===