Add PHP bindings for setting and getting the image resolution

We expose the image resolution related GD functionality to userland
by introducing `imagesetresolution()`, `imageresolutionx()` and
`imageresolutiony()` as simple wrappers.

Author: cmb69

ext/gd/gd.c

@@ -821,6 +821,20 @@ ZEND_BEGIN_ARG_INFO(arginfo_imagesetinterpolation, 0)
 	ZEND_ARG_INFO(0, method)
 ZEND_END_ARG_INFO()
 
+ZEND_BEGIN_ARG_INFO(arginfo_imagesetresolution, 0)
+	ZEND_ARG_INFO(0, im)
+	ZEND_ARG_INFO(0, res_x)
+	ZEND_ARG_INFO(0, res_y)
+ZEND_END_ARG_INFO()
+
+ZEND_BEGIN_ARG_INFO(arginfo_imageresolutionx, 0)
+	ZEND_ARG_INFO(0, im)
+ZEND_END_ARG_INFO()
+
+ZEND_BEGIN_ARG_INFO(arginfo_imageresolutiony, 0)
+	ZEND_ARG_INFO(0, im)
+ZEND_END_ARG_INFO()
+
 /* }}} */
 
 /* {{{ gd_functions[]
@@ -965,6 +979,10 @@ const zend_function_entry gd_functions[] = {
 	PHP_FE(imagefilter,     						arginfo_imagefilter)
 	PHP_FE(imageconvolution,						arginfo_imageconvolution)
 
+	PHP_FE(imagesetresolution,						arginfo_imagesetresolution)
+	PHP_FE(imageresolutionx,						arginfo_imageresolutionx)
+	PHP_FE(imageresolutiony,						arginfo_imageresolutiony)
+
 	PHP_FE_END
 };
 /* }}} */
@@ -4991,6 +5009,64 @@ PHP_FUNCTION(imagesetinterpolation)
 }
 /* }}} */
 
+/* {{{ proto void imagesetresolution(resource im , int res_x, int res_y)
+   Set the resolution of the image in DPI. */
+PHP_FUNCTION(imagesetresolution)
+{
+	zval *IM;
+	gdImagePtr im;
+	zend_long res_x, res_y;
+
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "rll", &IM, &res_x, &res_y) == FAILURE)  {
+		return;
+	}
+
+	if ((im = (gdImagePtr)zend_fetch_resource(Z_RES_P(IM), "Image", le_gd)) == NULL) {
+		RETURN_FALSE;
+	}
+
+	gdImageSetResolution(im, res_x, res_y);
+}
+/* }}} */
+
+/* {{{ proto int imageresolutionx(resource im)
+   Get the horizontal resolution of the image in DPI. */
+PHP_FUNCTION(imageresolutionx)
+{
+	zval *IM;
+	gdImagePtr im;
+
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "r", &IM) == FAILURE)  {
+		return;
+	}
+
+	if ((im = (gdImagePtr)zend_fetch_resource(Z_RES_P(IM), "Image", le_gd)) == NULL) {
+		RETURN_FALSE;
+	}
+
+	RETURN_LONG(gdImageResolutionX(im));
+}
+/* }}} */
+
+/* {{{ proto int imageresolutiony(resource im)
+   Get the vertical resolution of the image in DPI. */
+PHP_FUNCTION(imageresolutiony)
+{
+	zval *IM;
+	gdImagePtr im;
+
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "r", &IM) == FAILURE)  {
+		return;
+	}
+
+	if ((im = (gdImagePtr)zend_fetch_resource(Z_RES_P(IM), "Image", le_gd)) == NULL) {
+		RETURN_FALSE;
+	}
+
+	RETURN_LONG(gdImageResolutionY(im));
+}
+/* }}} */
+
 /*
  * Local variables:
  * tab-width: 4

ext/gd/php_gd.h

@@ -198,6 +198,10 @@ PHP_FUNCTION(imagexbm);
 PHP_FUNCTION(imagefilter);
 PHP_FUNCTION(imageconvolution);
 
+PHP_FUNCTION(imagesetresolution);
+PHP_FUNCTION(imageresolutionx);
+PHP_FUNCTION(imageresolutiony);
+
 PHP_GD_API int phpi_get_le_gd(void);
 
 #else

ext/gd/tests/imageresolution_jpeg.phpt

@@ -0,0 +1,32 @@
+--TEST--
+Set and get image resolution of JPEG images
+--SKIPIF--
+<?php
+if (!extension_loaded('gd')) die('skip gd extension not available');
+if (!(imagetypes() & IMG_JPEG)) die('skip JPEG support not available');
+?>
+--FILE--
+<?php
+$filename = __DIR__ . DIRECTORY_SEPARATOR . 'imageresolution_jpeg.jpeg';
+
+$im = imagecreate(100, 100);
+imagesetresolution($im, 72, 300);
+$red = imagecolorallocate($im, 255, 0, 0);
+imagefilledrectangle($im, 0,0, 99,99, $red);
+imagejpeg($im, $filename);
+
+$im = imagecreatefromjpeg($filename);
+var_dump(
+    imageresolutionx($im),
+    imageresolutiony($im)
+);
+?>
+===DONE===
+--EXPECT--
+int(72)
+int(300)
+===DONE===
+--CLEAN--
+<?php
+@unlink(__DIR__ . DIRECTORY_SEPARATOR . 'imageresolution_jpeg.jpeg');
+?>

ext/gd/tests/imageresolution_png.phpt

@@ -0,0 +1,31 @@
+--TEST--
+Set and get image resolution of PNG images
+--SKIPIF--
+<?php
+if (!extension_loaded('gd')) die('skip gd extension not available');
+?>
+--FILE--
+<?php
+$filename = __DIR__ . DIRECTORY_SEPARATOR . 'imageresolution_png.png';
+
+$im = imagecreate(100, 100);
+imagesetresolution($im, 72, 300);
+$red = imagecolorallocate($im, 255, 0, 0);
+imagefilledrectangle($im, 0,0, 99,99, $red);
+imagepng($im, $filename);
+
+$im = imagecreatefrompng($filename);
+var_dump(
+    imageresolutionx($im),
+    imageresolutiony($im)
+);
+?>
+===DONE===
+--EXPECT--
+int(72)
+int(300)
+===DONE===
+--CLEAN--
+<?php
+@unlink(__DIR__ . DIRECTORY_SEPARATOR . 'imageresolution_png.png');
+?>