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package com.foreach.imageserver.math;
import com.foreach.imageserver.dto.CropDto;
import com.foreach.imageserver.dto.DimensionsDto;
import com.foreach.imageserver.dto.ImageResolutionDto;
import lombok.NonNull;
import org.springframework.util.Assert;
/**
* Utility methods to calculate/translate DTO instances.
*
* @author Arne Vandamme
*/
public class ImageServerConversionUtils
{
private ImageServerConversionUtils() {
}
public static AspectRatio calculateAspectRatio( ImageResolutionDto resolutionDto ) {
return calculateAspectRatio( resolutionDto.getDimensions() );
}
public static AspectRatio calculateAspectRatio( DimensionsDto dimensions ) {
return new AspectRatio( dimensions.getWidth(), dimensions.getHeight() );
}
/**
* This will extend an existing crop to match a given aspect ratio.
* The center point of the crop will be kept, so extending will happen equally on all sides involved.
* This can return a crop with negative x and y coordinates.
* Use {@link #moveToFit(CropDto, DimensionsDto)} if you also want the crop to be moved about to fit it
* in the visible coordinates box.
*
* Crop parameters like source and box will be kept.
*
* @param original crop coordinates
* @param aspectRatio the crop should match
* @return modified crop
* @see #moveToFit(CropDto, DimensionsDto)
*/
public static CropDto extendCrop( CropDto original, AspectRatio aspectRatio ) {
CropDto cropDto = new CropDto( original );
DimensionsDto cropDimensions = cropDto.getDimensions();
cropDimensions = normalize( cropDimensions, aspectRatio );
cropDto.setX( cropDto.getX() - ( cropDimensions.getWidth() - cropDto.getWidth() ) / 2 );
cropDto.setY( cropDto.getY() - ( cropDimensions.getHeight() - cropDto.getHeight() ) / 2 );
cropDto.setWidth( cropDimensions.getWidth() );
cropDto.setHeight( cropDimensions.getHeight() );
return cropDto;
}
/**
* This will shrink an existing crop to match a given aspect ratio.
* The center point of the crop will be kept. Assuming that the original crop had valid coordinates,
* this will result in a valid crop.
*
* Crop parameters like source and box will be kept.
*
* @param original crop coordinates
* @param aspectRatio the crop should match
* @return modified crop
*/
public static CropDto shrinkCrop( CropDto original, AspectRatio aspectRatio ) {
CropDto cropDto = new CropDto( original );
DimensionsDto originalDimensions = cropDto.getDimensions();
DimensionsDto cropDimensions = normalize( originalDimensions, aspectRatio );
cropDimensions = scaleToFitIn( cropDimensions, originalDimensions );
cropDto.setX( cropDto.getX() + ( cropDto.getWidth() - cropDimensions.getWidth() ) / 2 );
cropDto.setY( cropDto.getY() + ( cropDto.getHeight() - cropDimensions.getHeight() ) / 2 );
cropDto.setWidth( cropDimensions.getWidth() );
cropDto.setHeight( cropDimensions.getHeight() );
return cropDto;
}
/**
* Will shift a crop to fit entirely inside the box. Usually used after {@link #extendCrop(CropDto, AspectRatio)}
* to verify that the resulting extension does not surpass the box boundaries. This counters the center point
* based extending of a crop.
*
* This function will throw an exception if it is not possible to fit the crop inside the box.
*
* @param original crop coordinates
* @param box the crop should fit in
* @return modified crop
* @throws IllegalArgumentException if the crop dimensions are impossible to fit in the box
*/
public static CropDto moveToFit( CropDto original, DimensionsDto box ) {
CropDto cropDto = new CropDto( original );
if ( !fitsIn( cropDto.getDimensions(), box ) ) {
throw new IllegalArgumentException(
"Crop dimensions are larger than the box dimensions - impossible to fit" );
}
if ( cropDto.getX() < 0 ) {
cropDto.setX( 0 );
}
if ( cropDto.getY() < 0 ) {
cropDto.setY( 0 );
}
if ( cropDto.getX() + cropDto.getWidth() > box.getWidth() ) {
cropDto.setX( box.getWidth() - cropDto.getWidth() );
}
if ( cropDto.getY() + cropDto.getHeight() > box.getHeight() ) {
cropDto.setY( box.getHeight() - cropDto.getHeight() );
}
return cropDto;
}
/**
* Will calculate the unknown dimensions for the original according to the boundaries specified.
* Any unknown dimensions will be scaled according to the aspect ratio of the boundaries.
*
* @param original dimensions
* @param boundaries for the new dimensions
* @return normalized dimensions
*/
public static DimensionsDto normalize( DimensionsDto original, DimensionsDto boundaries ) {
DimensionsDto normalized = new DimensionsDto( original.getWidth(), original.getHeight() );
AspectRatio originalAspectRatio = calculateAspectRatio( boundaries );
if ( original.getWidth() == 0 && original.getHeight() == 0 ) {
normalized.setWidth( boundaries.getWidth() );
normalized.setHeight( boundaries.getHeight() );
}
else if ( original.getHeight() == 0 ) {
normalized.setHeight( originalAspectRatio.calculateHeightForWidth( original.getWidth() ) );
}
else if ( original.getWidth() == 0 ) {
normalized.setWidth( originalAspectRatio.calculateWidthForHeight( original.getHeight() ) );
}
return normalized;
}
/**
* Will verify and modify the dimensions so that they match the aspect ratio.
* The resulting dimensions will never be smaller than the original one and always
* one of the original dimensions will be kept.
*
* @param original dimensions
* @param aspectRatio to use when normalizing the dimensions
* @return normalized dimensions
*/
public static DimensionsDto normalize( DimensionsDto original, AspectRatio aspectRatio ) {
DimensionsDto normalized = new DimensionsDto( original.getWidth(), original.getHeight() );
if ( !calculateAspectRatio( normalized ).equals( aspectRatio ) ) {
int newWidth = aspectRatio.calculateWidthForHeight( normalized.getHeight() );
if ( newWidth < normalized.getWidth() ) {
normalized.setHeight( aspectRatio.calculateHeightForWidth( normalized.getWidth() ) );
}
else {
normalized.setWidth( newWidth );
}
}
return normalized;
}
/**
* Will translate a crop to fit inside the box specified.
* This requires the source dimensions of the crop to be set.
*
* @param original crop
* @param box to use for translating the crop coordinates
* @return normalized crop
*/
public static CropDto normalize( CropDto original, DimensionsDto box ) {
if ( original.getSource() == null || original.getSource().equals( new DimensionsDto() ) ) {
throw new IllegalArgumentException( "Normalizing a crop requires a valid source to be set." );
}
CropDto translated = new CropDto( original );
// Translate the crop coordinates to fit with the new box
DimensionsDto newSource = scaleToFitIn( original.getSource(), box );
translateCropToNewSource( translated, newSource );
translated.setSource( newSource );
translated.setBox( box );
// Ensure the resulting crop is valid
if ( translated.getWidth() == 0 || translated.getHeight() == 0 ) {
throw new RuntimeException( "Could not process crop: resulted in an illegal width or height of 0" );
}
return translated;
}
private static void translateCropToNewSource( CropDto crop, DimensionsDto newDimensions ) {
int leftX = crop.getX();
int leftY = crop.getY();
int rightX = leftX + crop.getWidth();
int rightY = leftY + crop.getHeight();
DimensionsDto source = crop.getSource();
leftX = snap( leftX, source.getWidth() );
leftY = snap( leftY, source.getHeight() );
rightX = snap( rightX, source.getWidth() );
rightY = snap( rightY, source.getHeight() );
if ( !newDimensions.equals( source ) ) {
double modX = (double) newDimensions.getWidth() / source.getWidth();
double modY = (double) newDimensions.getHeight() / source.getHeight();
crop.setX( Double.valueOf( leftX * modX ).intValue() );
crop.setY( Double.valueOf( leftY * modY ).intValue() );
crop.setWidth( Double.valueOf( ( rightX - leftX ) * modX ).intValue() );
crop.setHeight( Double.valueOf( ( rightY - leftY ) * modY ).intValue() );
}
else {
crop.setX( leftX );
crop.setY( leftY );
crop.setWidth( rightX - leftX );
crop.setHeight( rightY - leftY );
}
}
private static int snap( int pos, int max ) {
if ( pos < 0 ) {
return 0;
}
else if ( pos > max ) {
return max;
}
return pos;
}
/**
* Will downscale the dimensions to fit in the boundaries if they are larger.
*
* @param original dimensions
* @param box that the translated dimensions should fit in
* @return translated dimensions
*/
public static DimensionsDto scaleToFitIn( DimensionsDto original, DimensionsDto box ) {
DimensionsDto normalized = normalize( original, box );
DimensionsDto scaled = new DimensionsDto( normalized.getWidth(), normalized.getHeight() );
AspectRatio aspectRatio = calculateAspectRatio( normalized );
if ( !fitsIn( normalized, box ) ) {
if ( aspectRatio.isLargerOnWidth() ) {
scaled.setWidth( box.getWidth() );
scaled.setHeight( aspectRatio.calculateHeightForWidth( box.getWidth() ) );
}
else {
scaled.setHeight( box.getHeight() );
scaled.setWidth( aspectRatio.calculateWidthForHeight( box.getHeight() ) );
}
if ( !fitsIn( scaled, box ) ) {
// Reverse the side as scaling basis, we made the wrong decision
if ( aspectRatio.isLargerOnWidth() ) {
scaled.setHeight( box.getHeight() );
scaled.setWidth( aspectRatio.calculateWidthForHeight( box.getHeight() ) );
}
else {
scaled.setWidth( box.getWidth() );
scaled.setHeight( aspectRatio.calculateHeightForWidth( box.getWidth() ) );
}
}
}
return scaled;
}
/**
* Checks if the area represented by dimensions fits inside the area defined by the box (the original
* area should be the same surface or smaller).
*
* @param original dimensions to check
* @param boundaries that the dimensions should fit in
* @return true if dimensions fit
*/
public static boolean fitsIn( DimensionsDto original, DimensionsDto boundaries ) {
return original.getWidth() <= boundaries.getWidth() && original.getHeight() <= boundaries.getHeight();
}
/**
* Checks if a crop is entirely positioned within a box. The crop dimensions should be smaller or equal
* to the box dimensions, and the left top coordinates should not be negative.
*
* @param crop to check
* @param box that should contain the crop
* @return true if crop fits
*/
public static boolean isWithinBox( CropDto crop, DimensionsDto box ) {
return crop.getX() >= 0 && crop.getY() >= 0
&& fitsIn( crop.getDimensions(), box )
&& ( crop.getX() + crop.getWidth() ) <= box.getWidth()
&& ( crop.getY() + crop.getHeight() ) <= box.getHeight();
}
public static int calculateDistance( ImageResolutionDto from, ImageResolutionDto to ) {
return calculateDistance( from.getDimensions(), to.getDimensions() );
}
/**
* Calculates the distance between two dimensions. If the dimensions are exactly the same, the distance is 0.
* If the first dimensions fits entirely in the second, the distance will be positive. The larger the second
* dimension, the greater the distance number. If the first dimension is larger than the second dimension, the
* distance number will be negative. Distances closer to 0 indicate how much smaller the scond dimension is.
*
* A dimension is considered smaller as soon as a single side is smaller. Calculating the distance is
* impossible if any of the arguments have an unknown dimension.
*
* The actual distance number is the delta between the two surfaces. If the surface is the same (but dimensions
* are reversed), then the distance will be -1.
*
* @param from dimension
* @param to dimension
* @return distance number
*/
public static int calculateDistance( @NonNull DimensionsDto from, @NonNull DimensionsDto to ) {
Assert.isTrue( from.getWidth() > 0 && from.getHeight() > 0 && to.getWidth() > 0 && to.getHeight() > 0,
"Width and Height must be greater than 0" );
if ( from.equals( to ) ) {
return 0;
}
if ( fitsIn( from, to ) ) {
return Math.abs( ( to.getWidth() * to.getHeight() ) - ( from.getWidth() * from.getHeight() ) );
}
int distance = -Math.abs( ( to.getWidth() * to.getHeight() ) - ( from.getWidth() * from.getHeight() ) );
return distance == 0 ? -1 : distance;
}
}