fix(ios): prevent crash when printing images without internet connection (#229)

* fix(ios): prevent crash when printing images without internet connection

- Add validation checks in ImageManager.m to handle nil data and invalid image dimensions
- Add error handling in ThePrinter.m to return EPOS2_ERR_PARAM instead of crashing
- Prevent UIGraphicsBeginImageContext crash with invalid size parameters
- Fix division by zero in getImageCGSize when image width is 0

Fixes crash: UIGraphicsBeginImageContext() failed to allocate CGBitampContext: size={472, 0}

* fix: review comments

* fix: error code returned

Author: tolypash

package/ios/ImageManager.m

@@ -38,7 +38,11 @@ + (UIImage *)getImageFromDictionarySource:(NSDictionary *)imageObj
     if([urlString hasPrefix: @"http"] || [urlString hasPrefix: @"https"]) {
         NSURL *url = [NSURL URLWithString: urlString];
         NSData *data = [NSData dataWithContentsOfURL:url];
-        imageData = [[UIImage alloc] initWithData:data];
+        if (data && data.length > 0) {
+            imageData = [[UIImage alloc] initWithData:data];
+        } else {
+            imageData = nil;
+        }
     } else {
         imageData = [RCTConvert UIImage:imageObj];
     }

package/ios/ThePrinter.m

@@ -387,6 +387,11 @@ -(int) addImage: (NSDictionary *)source
             return EPOS2_ERR_MEMORY;
         }
         UIImage *data = [ImageManager getImageFromDictionarySource:source];
+        // Check if image loading failed (e.g., due to network issues)
+        if (data == nil) {
+            return EPOS2_ERR_FAILURE;
+        }
+        
         CGSize size = [ImageManager getImageCGSize:data width:width];
         UIImage *scaledImage = [ImageManager scaleImage:data size:size];