aaronpeterson · August 9, 2014 03:55 · Oct 23, 2013 · Oct 23, 2013 · Oct 23, 2013 · Oct 23, 2013
diff --git a/main.m b/main.m
@@ -1,10 +1,16 @@
-//
 //  main.m
 //  creategif
 //
 //  Created by Kevin Meaney on 21/10/2013.
-//  Copyright (c) 2013 Kevin Meaney. All rights reserved.
-//
+
+// I've briefly blogged about it here:
+// http://blog.yvs.eu.com/2013/10/creating-gif-animations-using-coreimagequartz
+// The following code is all that is all the code needed for a creating a command line tool to generate
+// a gif animation from image files. 
+// The main limitation with this code is that apart from the frame delay time of 0.1 second, every
+// other frame delay time has to be a multiple of 0.5 seconds. There is no checking that the frame size
+// of each image file is the same or resizing of frames to make them conform.
+// I provide no warranty as to the operation of this code.
 
 #import <Foundation/Foundation.h>
 @import ImageIO;

diff --git a/main.m b/main.m
@@ -123,7 +123,7 @@ int main(int argc, const char * argv[])
                                         (__bridge CFDictionaryRef)gifFileProps);
         if (!imageDest)
         {
-            printf("Couldn't create image destination");
+            printf("Couldn't create image destination\n");
             return 0;
         }
 

diff --git a/main.m b/main.m
@@ -14,10 +14,9 @@ void PrintUsage()
 	printf("creategif - usage:\n");
 	printf("	./creategif [-parameter <value> ...], filename1, filename2, ...\n");
 	printf("	 Parameters are preceded by a -<parameterName>.  The order of the parameters is unimportant.\n");
-	printf("	 All the input image filenames follow the parameters.\n");
+	printf("	 All the input image filenames follow the parameters and their values.\n");
 	printf("	 You probably need to escape or quote paths especially if the paths includes spaces etc..\n");
-    printf("	 Only one of -delaytime or -unclampeddelaytime needs to be specified, both can be.\n");
-    printf("	 If the output file already exists then it will be deleted prior to saving the new file if allowed.\n");
+        printf("	 If the output file already exists then it will be overwritten if possible.\n");
 	printf("	 Available parameters are:\n");
 	printf("	 	-outputfile <output file path which should finish with a gif extension>\n");
 	printf("	 	-delaytime <should be a floating point number above 0.1>\n");

diff --git a/main.m b/main.m
@@ -0,0 +1,173 @@
+//
+//  main.m
+//  creategif
+//
+//  Created by Kevin Meaney on 21/10/2013.
+//  Copyright (c) 2013 Kevin Meaney. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+@import ImageIO;
+
+void PrintUsage()
+{
+	printf("creategif - usage:\n");
+	printf("	./creategif [-parameter <value> ...], filename1, filename2, ...\n");
+	printf("	 Parameters are preceded by a -<parameterName>.  The order of the parameters is unimportant.\n");
+	printf("	 All the input image filenames follow the parameters.\n");
+	printf("	 You probably need to escape or quote paths especially if the paths includes spaces etc..\n");
+    printf("	 Only one of -delaytime or -unclampeddelaytime needs to be specified, both can be.\n");
+    printf("	 If the output file already exists then it will be deleted prior to saving the new file if allowed.\n");
+	printf("	 Available parameters are:\n");
+	printf("	 	-outputfile <output file path which should finish with a gif extension>\n");
+	printf("	 	-delaytime <should be a floating point number above 0.1>\n");
+//	printf("	 	-unclampeddelaytime <should be a floating point number above 0.1>\n");
+	printf("	Sample export lines:\n");
+	printf("	./creategif -outputfile blahblah.gif -delaytime 0.4 -unclampeddelaytime 0.4 image1.png image2.png image3.png image4.png\n");
+	printf("	./creategif -outputfile \"Users/ktam/gifs/blahblah.gif\" -delaytime 1.0 image1.png image2.png image3.png image4.png\n");
+}
+
+BOOL GetFloatFromString(NSString *string, CGFloat *value)
+{
+    NSScanner *scanner = [[NSScanner alloc] initWithString:string];
+    CGFloat floatVal;
+    BOOL gotValue = [scanner scanDouble:&floatVal];
+    if (gotValue)
+    {
+        *value = floatVal;
+    }
+    return gotValue;
+}
+
+NSMutableArray *inputImageList;
+NSString *outFilePath;
+CGFloat delayTime;
+CGFloat unclampedDelayTime;
+BOOL gotDelayTime = NO;
+BOOL gotUnclampedDelayTime = NO;
+
+bool GetArgs(int argc, const char **argv) // returns true if successful.
+{
+    bool success = true;
+
+    argv++;
+    argc--;
+    const char *args;
+    // Get the parameters
+    while (argc > 0 && **argv == '-')
+    {
+		args = *argv;
+        argv++;
+        argc--;
+
+        if ( ! strcmp ( args, "-outputfile" ) )
+		{
+            outFilePath = @(*argv++);
+			argc--;
+		}
+        else if ( ! strcmp( args, "-delaytime" ))
+        {
+            gotDelayTime = GetFloatFromString(@(*argv++), &delayTime);
+            argc--;
+        }
+/*        else if ( ! strcmp( args, "-unclampeddelaytime"))
+        {
+            gotUnclampedDelayTime = GetFloatFromString(@(*argv++), &unclampedDelayTime);
+            argc--;
+        }
+*/
+    }
+
+    if (!(gotDelayTime || gotUnclampedDelayTime))
+        success = false;
+
+    if (!outFilePath)
+        success = false;
+
+    // If we've got to the end of arguments and there are no input files then bail.
+    if (!success)
+        return success;
+
+    inputImageList = [[NSMutableArray alloc] initWithCapacity:0];
+//    [inputImageList addObject:@(args)];
+    // Finished getting parameters. Now get list of source files. 1 image per file.
+    while (argc > 0)
+    {
+        args = *argv;
+        argv++;
+        argc--;
+        [inputImageList addObject:@(args)];
+    }
+    if (!inputImageList || [inputImageList count] == 0)
+        success = false;
+
+    return success;
+}
+
+int main(int argc, const char * argv[])
+{
+    @autoreleasepool
+    {
+        if (!GetArgs(argc, argv))
+        {
+            PrintUsage();
+            return 0;
+        }
+
+        NSDictionary *gifFileProps = @{ @"{GIF}" : @{ @"HasGlobalColorMap" : @YES,
+                                                      @"LoopCount" : @(0) } };
+        NSURL *outputURL = [[NSURL alloc] initFileURLWithPath:outFilePath isDirectory:NO];
+        CGImageDestinationRef imageDest;
+        imageDest = CGImageDestinationCreateWithURL((__bridge CFURLRef)outputURL,
+                                        CFSTR("com.compuserve.gif"),
+                                        [inputImageList count],
+                                        (__bridge CFDictionaryRef)gifFileProps);
+        if (!imageDest)
+        {
+            printf("Couldn't create image destination");
+            return 0;
+        }
+
+        CGImageDestinationSetProperties(imageDest,
+                                        (__bridge CFDictionaryRef)gifFileProps);
+
+        for (NSString *inputFile in inputImageList)
+        {
+            NSString *expandedString = [inputFile stringByExpandingTildeInPath];
+            NSURL *sourceFile = [[NSURL alloc] initFileURLWithPath:expandedString
+                                                       isDirectory:NO];
+            CGImageSourceRef imageSource;
+            imageSource = CGImageSourceCreateWithURL((__bridge CFURLRef)sourceFile,
+                                                     NULL);
+            if (!imageSource)
+            {
+                printf("Invalid source file path\n");
+                return 0;
+            }
+
+            if (CGImageSourceGetCount(imageSource))
+            {
+                CGImageRef theImage;
+                theImage = CGImageSourceCreateImageAtIndex(imageSource, 0, NULL);
+                if (theImage)
+                {
+                    NSMutableDictionary *gifFrameProps;
+                    gifFrameProps = [[NSMutableDictionary alloc] initWithCapacity:0];
+                    if (gotDelayTime)
+                        [gifFrameProps setObject:@(delayTime) forKey:@"DelayTime"];
+//                    if (gotUnclampedDelayTime)
+//                        [gifFrameProps setObject:@(unclampedDelayTime)
+//                                                forKey:@"UnclampedDelayTime"];
+                    NSDictionary *frameProps = @{ @"{GIF}" : gifFrameProps };
+                    CGImageDestinationAddImage(imageDest, theImage,
+                                            (__bridge CFDictionaryRef)frameProps);
+                    CFRelease(theImage);
+                }
+            }
+            CFRelease(imageSource);
+        }
+        CGImageDestinationFinalize(imageDest);
+        CFRelease(imageDest);
+    }
+    return 0;
+}
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