Changes to how the requested width and height are handled by View cla…

…ss as well as how the resolution level is calculated.

Fixes problems with fitting images into bounding boxes and now correctly selects appropriate resolution level in all cases. Fixes #273

ChangeLog

@@ -1,3 +1,9 @@
+16/10/2024:
+	- Changes to how the requested width and height are handled by View class as well as how the resolution level
+	  is calculated. Fixes problems with fitting images into bounding boxes and now correctly selects appropriate
+	  resolution level in all cases. Fixes https://github.com/ruven/iipsrv/issues/273
+
+
 02/10/2024:
 	- Re-factoring of tile byte size check to work cleanly for both JPEG and WEBP and to avoid having to sometimes
 	  reallocate memory

src/CVT.cc

@@ -102,8 +102,9 @@ void CVT::send( Session* session ){
     view_width = session->view->getViewWidth();
     view_height = session->view->getViewHeight();
 
-    resampled_width = session->view->getRequestWidth();
-    resampled_height = session->view->getRequestHeight();
+    vector<unsigned int> requestSize = session->view->getRequestSize();
+    resampled_width = requestSize[0];
+    resampled_height = requestSize[1];
 
     if( session->loglevel >= 3 ){
       *(session->logfile) << "CVT :: Region: " << view_left << "," << view_top
@@ -116,8 +117,9 @@ void CVT::send( Session* session ){
     view_top = 0;
     view_width = im_width;
     view_height = im_height;
-    resampled_width = session->view->getRequestWidth();
-    resampled_height = session->view->getRequestHeight();
+    vector<unsigned int> requestSize = session->view->getRequestSize();
+    resampled_width = requestSize[0];
+    resampled_height = requestSize[1];
   }
 
 
@@ -128,19 +130,6 @@ void CVT::send( Session* session ){
     if(resampled_height > im_height) resampled_height = im_height;
   }
 
-  // If we have requested that the aspect ratio be maintained, make sure the final image fits *within* the requested size.
-  // Don't adjust images if we have less than 0.1% difference as this is often due to rounding in resolution levels
-  if( session->view->maintain_aspect ){
-    vector<float> size = session->view->getViewSize();
-    float ratio = ((float)resampled_width/size[0]) / ((float)resampled_height/size[1]);
-    if( ratio < 0.999 ){
-      resampled_height = (unsigned int) round( ((float)resampled_width/size[0]) * size[1] );
-    }
-    else if( ratio > 1.001 ){
-      resampled_width = (unsigned int) round( ((float)resampled_height/size[1]) * size[0] );
-    }
-  }
-
 
   // Make sure we don't have zero sized dimensions
   if( resampled_width == 0 ) resampled_width = session->view->getMinSize();

src/IIIF.cc

@@ -543,7 +543,7 @@ void IIIF::run( Session* session, const string& src )
       // Check for malformed upscaling request
       if( iiif_version >= 3 ){
 	if( session->view->allow_upscaling == false &&
-	    ( requested_width > width || requested_height > height ) ){
+	    ( requested_width > (width*region[2]) || requested_height > (height*region[3]) ) ){
 	  throw invalid_argument( "IIIF: upscaling should be prefixed with ^" );
 	}
       }

src/View.cc

@@ -62,8 +62,9 @@ unsigned int View::getResolution(){
   unsigned int i;
 
   // Note that we use floor() as that is how our resolutions are calculated
-  if( requested_width ) View::calculateResolution( width, floor((float)requested_width/(float)view_width) );
-  if( requested_height ) View::calculateResolution( height, floor((float)requested_height/(float)view_height) );
+  vector<unsigned int> requested_size = View::getRequestSize();
+  View::calculateResolution( width, floor((float)requested_size[0]/(float)view_width) );
+  View::calculateResolution( height, floor((float)requested_size[1]/(float)view_height) );
 
   res_width = width;
   res_height = height;
@@ -224,45 +225,53 @@ unsigned int View::getViewHeight(){
 }
 
 
-unsigned int View::getRequestWidth(){
+vector<unsigned int> View::getRequestSize(){
 
-  // If our requested width has not been set, but height has, return a width proportional to
-  // this requested height
   unsigned int w = requested_width;
-  if( requested_width == 0 ){
-    if( requested_height != 0 ){
-      w = (unsigned int) round( (float)(getViewWidth()*requested_height) / (float)getViewHeight() );
-    }
-
-    // If no width or height has been set, use the full image size
-    else if( requested_height==0 ) w = width;
-  }
+  unsigned int h = requested_height;
 
-  // Limit our requested width to the maximum export size if we have set a limit
-  if( max_size > 0 && w > (unsigned int) max_size ) w = max_size;
-
-  return w;
-}
+  // Calculate aspect ratio
+  float ratio = (view_width * width) / (view_height * height);
 
+  if( requested_width == 0 && requested_height != 0 ){
+    w = (unsigned int) round( (float)requested_height * ratio );
+  }
+  else if( requested_height == 0 && requested_width != 0 ){
+    h = (unsigned int) round( (float)requested_width / ratio );
+  }
+  else if( requested_width == 0 && requested_height == 0 ){
+    w = width;
+    h = height;
+  }
+  // If both width and height are set, restrict image to this bounding box
+  else if( requested_width != 0 && requested_height != 0 && maintain_aspect ){
+    float xscale = requested_width / (view_width*width);
+    float yscale = requested_height / (view_height*height);
+    // Fit to the axis requiring the most scaling (smallest factor)
+    if( xscale > yscale ) w = (unsigned int) (unsigned int) round( (float)requested_height * ratio );
+    else h = (unsigned int) round( (float)requested_width / ratio );
+  }
 
-unsigned int View::getRequestHeight(){
 
-  // If our requested height has not been set, but the width has, return a height proportional to
-  // this requested width
-  unsigned int h = requested_height;
-  if( requested_height == 0 ){
-    if( requested_width != 0 ){
-      h = (unsigned int) round( (float)(getViewHeight()*requested_width) / (float)getViewWidth() );
+  // Limit our requested size to the maximum output size
+  if( max_size > 0 && (w > (unsigned int) max_size || h > (unsigned int) max_size) ){
+    if( w > h ){
+      w = max_size;
+      h = round( (float)requested_width / ratio );
+    }
+    else if( h > w ){
+      h = max_size;
+      w = round( (float)requested_height * ratio );
+    }
+    else{
+      w = max_size;
+      h = max_size;
     }
-
-    // If no width or height has been set, use the full image size
-    else if( requested_width==0 ) h = height;
   }
 
-  // Limit our requested height to the maximum export size
-  if( max_size > 0 && h > (unsigned int) max_size ) h = max_size;
-
-  return h;
+  // Create and return our result
+  std::vector<unsigned int> size = { w, h };
+  return size;
 }
 
 

src/View.h

@@ -115,12 +115,12 @@ class View{
 
 
   /// Get the maximum allowed output size
-  /* @return maximum output dimension */
+  /** @return maximum output dimension */
   int getMaxSize(){ return max_size; };
 
 
   /// Get the minimum allowed output size
-  /* @return minimum output dimension */
+  /** @return minimum output dimension */
   unsigned int getMinSize(){ return min_size; };
 
 
@@ -130,7 +130,7 @@ class View{
 
 
   /// Get the allow_upscaling flag
-  /* @return true or false */
+  /** @return true or false */
   bool allowUpscaling(){ return allow_upscaling; };
 
 
@@ -155,21 +155,16 @@ class View{
   void setMaxResolutions( unsigned int r ){ max_resolutions = r; resolution=r-1; };
 
 
-  /// Get the size of the requested width
-  /* @return requested width */
-  unsigned int getRequestWidth();
-
-
   /// Set the size of the requested width
   /** @param w requested image width */
   void setRequestWidth( unsigned int w ){
     requested_width = w;
   };
 
 
-  /// Get the size of the requested height
-  /* @return requested height */
-  unsigned int getRequestHeight();
+  /// Get requested image size
+  /** @return output size as a vector */
+  std::vector<unsigned int> getRequestSize();
 
 
   /// Set the size of the requested height
@@ -180,12 +175,12 @@ class View{
 
 
   /// Return the resolution level needed for the requested view
-  /* @return requested resolution level */
+  /** @return requested resolution level */
   unsigned int getResolution();
 
 
   /// Return the scaling required in case our requested width or height is in between available resolutions
-  /* @return scaling factor */
+  /** @return scaling factor */
   float getScale();
 
 
@@ -236,39 +231,39 @@ class View{
   int getLayers();
 
   /// Return the image width at our requested resolution
-  /* @return image width */
+  /** @return image width */
   unsigned int getImageWidth(){ return width; };
 
   /// Return the image height at our requested resolution
-  /* @return image height */
+  /** @return image height */
   unsigned int getImageHeight(){ return height; };
 
   /// Return the left pixel of the viewport
-  /* @return position of left of viewport in pixels */
+  /** @return position of left of viewport in pixels */
   unsigned int getViewLeft() ;
 
   /// Return the top pixel of the viewport
-  /* @return position of top of viewport in pixels */
+  /** @return position of top of viewport in pixels */
   unsigned int getViewTop();
 
   /// Return the pixel width of the viewport
-  /* @return width of viewport in pixels */
+  /** @return width of viewport in pixels */
   unsigned int getViewWidth();
 
   /// Return the pixel height of the viewport
-  /* @return height of viewport in pixels */
+  /** @return height of viewport in pixels */
   unsigned int getViewHeight();
 
   /// Indicate whether the viewport has been set
-  /* @return boolean indicating whether viewport specified */
+  /** @return boolean indicating whether viewport specified */
   bool viewPortSet();
 
   /// Set rotation
   /** @param r angle of rotation in degrees */
   void setRotation( float r ){ rotation = r; };
 
   /// Get rotation
-  /* @return requested rotation angle in degrees */
+  /** @return requested rotation angle in degrees */
   float getRotation(){ return rotation; };
 
   /// Whether view requires floating point processing