Update the PDF demo and test cases

Examples/SDWebImage Demo/MasterViewController.m

@@ -75,6 +75,7 @@
                     @"https://nokiatech.github.io/heif/content/images/ski_jump_1440x960.heic",
                     @"https://nokiatech.github.io/heif/content/image_sequences/starfield_animation.heic",
                     @"https://s2.ax1x.com/2019/11/01/KHYIgJ.gif",
+                    @"https://raw.githubusercontent.com/icons8/flat-color-icons/master/pdf/stack_of_photos.pdf",
                     @"https://nr-platform.s3.amazonaws.com/uploads/platform/published_extension/branding_icon/275/AmazonS3.png",
                     @"http://via.placeholder.com/200x200.jpg",
                     nil];

Tests/SDWebImage Tests.xcodeproj/project.pbxproj

@@ -14,6 +14,9 @@
 		322241802272F808002429DB /* SDUtilsTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 3222417E2272F808002429DB /* SDUtilsTests.m */; };
 		3226ECBB20754F7700FAFACF /* SDWebImageTestDownloadOperation.m in Sources */ = {isa = PBXBuildFile; fileRef = 3226ECBA20754F7700FAFACF /* SDWebImageTestDownloadOperation.m */; };
 		3226ECBC20754F7700FAFACF /* SDWebImageTestDownloadOperation.m in Sources */ = {isa = PBXBuildFile; fileRef = 3226ECBA20754F7700FAFACF /* SDWebImageTestDownloadOperation.m */; };
+		3234306223E2BAC800C290C8 /* TestImage.pdf in Resources */ = {isa = PBXBuildFile; fileRef = 3234306123E2BAC800C290C8 /* TestImage.pdf */; };
+		3234306323E2BAC800C290C8 /* TestImage.pdf in Resources */ = {isa = PBXBuildFile; fileRef = 3234306123E2BAC800C290C8 /* TestImage.pdf */; };
+		3234306423E2BAC800C290C8 /* TestImage.pdf in Resources */ = {isa = PBXBuildFile; fileRef = 3234306123E2BAC800C290C8 /* TestImage.pdf */; };
 		323B8E1F20862322008952BE /* SDWebImageTestLoader.m in Sources */ = {isa = PBXBuildFile; fileRef = 323B8E1E20862322008952BE /* SDWebImageTestLoader.m */; };
 		323B8E2020862322008952BE /* SDWebImageTestLoader.m in Sources */ = {isa = PBXBuildFile; fileRef = 323B8E1E20862322008952BE /* SDWebImageTestLoader.m */; };
 		324047442271956F007C53E1 /* TestEXIF.png in Resources */ = {isa = PBXBuildFile; fileRef = 324047432271956F007C53E1 /* TestEXIF.png */; };
@@ -107,6 +110,7 @@
 		3222417E2272F808002429DB /* SDUtilsTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = SDUtilsTests.m; sourceTree = "<group>"; };
 		3226ECB920754F7700FAFACF /* SDWebImageTestDownloadOperation.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = SDWebImageTestDownloadOperation.h; sourceTree = "<group>"; };
 		3226ECBA20754F7700FAFACF /* SDWebImageTestDownloadOperation.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = SDWebImageTestDownloadOperation.m; sourceTree = "<group>"; };
+		3234306123E2BAC800C290C8 /* TestImage.pdf */ = {isa = PBXFileReference; lastKnownFileType = image.pdf; path = TestImage.pdf; sourceTree = "<group>"; };
 		323B8E1D20862322008952BE /* SDWebImageTestLoader.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = SDWebImageTestLoader.h; sourceTree = "<group>"; };
 		323B8E1E20862322008952BE /* SDWebImageTestLoader.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = SDWebImageTestLoader.m; sourceTree = "<group>"; };
 		324047432271956F007C53E1 /* TestEXIF.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = TestEXIF.png; sourceTree = "<group>"; };
@@ -238,6 +242,7 @@
 				433BBBB81D7EF8260086B6E9 /* TestImage.png */,
 				327A418B211D660600495442 /* TestImage.heic */,
 				32905E63211D786E00460FCF /* TestImage.heif */,
+				3234306123E2BAC800C290C8 /* TestImage.pdf */,
 				327054E1206CEFF3006EA328 /* TestImageAnimated.apng */,
 				3297A09E23374D1600814590 /* TestImageAnimated.heic */,
 			);
@@ -443,6 +448,7 @@
 				3299228B2365DC6C00EAFD97 /* TestImage.heic in Resources */,
 				329922872365DC6C00EAFD97 /* TestLoopCount.gif in Resources */,
 				3299228C2365DC6C00EAFD97 /* TestImage.heif in Resources */,
+				3234306423E2BAC800C290C8 /* TestImage.pdf in Resources */,
 				329922892365DC6C00EAFD97 /* TestImageLarge.jpg in Resources */,
 				3299228A2365DC6C00EAFD97 /* TestImage.png in Resources */,
 				329922842365DC6C00EAFD97 /* MonochromeTestImage.jpg in Resources */,
@@ -461,6 +467,7 @@
 				32B99EA3203B31360017FD66 /* TestImage.gif in Resources */,
 				324047452271956F007C53E1 /* TestEXIF.png in Resources */,
 				32B99EA4203B31360017FD66 /* TestImage.jpg in Resources */,
+				3234306323E2BAC800C290C8 /* TestImage.pdf in Resources */,
 				32B99EA6203B31360017FD66 /* TestImage.png in Resources */,
 				3297A0A023374D1700814590 /* TestImageAnimated.heic in Resources */,
 				32B99EA2203B31360017FD66 /* MonochromeTestImage.jpg in Resources */,
@@ -479,6 +486,7 @@
 				5F7F38AD1AE2A77A00B0E330 /* TestImage.jpg in Resources */,
 				32905E64211D786E00460FCF /* TestImage.heif in Resources */,
 				43828A451DA67F9900000E62 /* TestImageLarge.jpg in Resources */,
+				3234306223E2BAC800C290C8 /* TestImage.pdf in Resources */,
 				433BBBB71D7EF8200086B6E9 /* TestImage.gif in Resources */,
 				433BBBB91D7EF8260086B6E9 /* TestImage.png in Resources */,
 				3297A09F23374D1700814590 /* TestImageAnimated.heic in Resources */,

Tests/Tests/SDImageCoderTests.m

@@ -156,22 +156,34 @@
         withLocalImageURL:heicURL
          supportsEncoding:supportsEncoding
            encodingFormat:SDImageFormatHEIC
-          isAnimatedImage:isAnimatedImage];
+          isAnimatedImage:isAnimatedImage
+            isVectorImage:NO];
     }
 }
 
+- (void)test17ThatPDFWorks {
+    NSURL *pdfURL = [[NSBundle bundleForClass:[self class]] URLForResource:@"TestImage" withExtension:@"pdf"];
+    [self verifyCoder:[SDImageIOCoder sharedCoder]
+    withLocalImageURL:pdfURL
+     supportsEncoding:NO
+       encodingFormat:SDImageFormatUndefined
+      isAnimatedImage:NO
+        isVectorImage:YES];
+}
+
 - (void)verifyCoder:(id<SDImageCoder>)coder
 withLocalImageURL:(NSURL *)imageUrl
  supportsEncoding:(BOOL)supportsEncoding
   isAnimatedImage:(BOOL)isAnimated {
-    [self verifyCoder:coder withLocalImageURL:imageUrl supportsEncoding:supportsEncoding encodingFormat:SDImageFormatUndefined isAnimatedImage:isAnimated];
+    [self verifyCoder:coder withLocalImageURL:imageUrl supportsEncoding:supportsEncoding encodingFormat:SDImageFormatUndefined isAnimatedImage:isAnimated isVectorImage:NO];
 }
 
 - (void)verifyCoder:(id<SDImageCoder>)coder
   withLocalImageURL:(NSURL *)imageUrl
    supportsEncoding:(BOOL)supportsEncoding
      encodingFormat:(SDImageFormat)encodingFormat
-    isAnimatedImage:(BOOL)isAnimated {
+    isAnimatedImage:(BOOL)isAnimated
+      isVectorImage:(BOOL)isVector {
     NSData *inputImageData = [NSData dataWithContentsOfURL:imageUrl];
     expect(inputImageData).toNot.beNil();
     SDImageFormat inputImageFormat = [NSData sd_imageFormatForImageData:inputImageData];
@@ -204,7 +216,18 @@ withLocalImageURL:(NSURL *)imageUrl
     CGFloat pixelHeight = inputImage.size.height;
     expect(pixelWidth).beGreaterThan(0);
     expect(pixelHeight).beGreaterThan(0);
-    // check thumnail with scratch
+    // check vector format supports thumbnail with screen size
+    if (isVector) {
+#if SD_UIKIT
+        CGFloat maxScreenSize = MAX(UIScreen.mainScreen.bounds.size.width, UIScreen.mainScreen.bounds.size.height);
+#else
+        CGFloat maxScreenSize = MAX(NSScreen.mainScreen.frame.size.width, NSScreen.mainScreen.frame.size.height);
+#endif
+        expect(pixelWidth).equal(maxScreenSize);
+        expect(pixelHeight).equal(maxScreenSize);
+    }
+    
+    // check thumbnail with scratch
     CGFloat thumbnailWidth = 50;
     CGFloat thumbnailHeight = 50;
     UIImage *thumbImage = [coder decodedImageWithData:inputImageData options:@{
@@ -213,7 +236,7 @@ withLocalImageURL:(NSURL *)imageUrl
     }];
     expect(thumbImage).toNot.beNil();
     expect(thumbImage.size).equal(CGSizeMake(thumbnailWidth, thumbnailHeight));
-    // check thumnail with aspect ratio limit
+    // check thumbnail with aspect ratio limit
     thumbImage = [coder decodedImageWithData:inputImageData options:@{
         SDImageCoderDecodeThumbnailPixelSize : @(CGSizeMake(thumbnailWidth, thumbnailHeight)),
         SDImageCoderDecodePreserveAspectRatio : @(YES)