/**
 * Copyright (c) 2011, The University of Southampton and the individual contributors.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 *   *  Redistributions of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 *
 *   *  Redistributions in binary form must reproduce the above copyright notice,
 *      this list of conditions and the following disclaimer in the documentation
 *      and/or other materials provided with the distribution.
 *
 *   *  Neither the name of the University of Southampton nor the names of its
 *      contributors may be used to endorse or promote products derived from this
 *      software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.openimaj.image.typography;

import java.text.AttributedCharacterIterator;
import java.text.AttributedString;

import org.openimaj.image.renderer.ImageRenderer;
import org.openimaj.image.typography.FontStyle.HorizontalAlignment;
import org.openimaj.image.typography.FontStyle.VerticalAlignment;
import org.openimaj.math.geometry.shape.Rectangle;

/**
 * The FontRenderer represents an object capable of rendering text with 
 * a given font and style to an image. 
 * 
 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
 *
 * @param <T> type of image pixels
 * @param <Q> type of {@link FontStyle}
 */
public abstract class FontRenderer<T, Q extends FontStyle<T>> {
        /**
         * Render the given text string to the image starting at (x, y) with the
         * given style.
         * 
         * @param renderer the renderer
         * @param text the text
         * @param x the x-ordinate
         * @param y the y-ordinate
         * @param style the style
         */
        public abstract void renderText(ImageRenderer<T,?> renderer, String text, int x, int y, Q style);
        
        /**
         * Calculate the bounding box of the rendered text with the given style. 
         * @param string the text
         * @param style the style
         * @return the bounding box
         */
        public abstract Rectangle getSize(String string, Q style);
        
        /**
         * Calculate the bounding box of the rendered text with the given style. 
         * @param string the text
         * @param x the x to render the font
         * @param y the y to render the font
         * @param sty the style
         * @return the bounding box
         */
        public Rectangle getBounds(String string, int x, int y, Q sty){
                Rectangle rect = this.getSize(string, sty);
                // if we have a non-standard horizontal alignment
                if ((sty.getHorizontalAlignment() != HorizontalAlignment.HORIZONTAL_LEFT)) {
                        // find the length of the string in pixels ...
                        float len = (float) rect.getWidth();
                        // if we are center aligned
                        if (sty.getHorizontalAlignment() == HorizontalAlignment.HORIZONTAL_CENTER) {
                                x -= len/2;
                        } else {
                                x -= len;
                        }
                        
                }
                
                if(sty.getVerticalAlignment() != VerticalAlignment.VERTICAL_TOP){
                        switch (sty.getVerticalAlignment()) {
                        case VERTICAL_BOTTOM:
                                y -= rect.getHeight();
                                break;
                        case VERTICAL_HALF:
                                y -= rect.getHeight()/2f;
                                break;
                        default:
                                break;
                        }
                }
                
                rect.x = x;
                rect.y = y;
                return rect;
        }
        
        
        /**
         * Render the given {@link AttributedString} to the image starting at (x,y).
         * @param <T> the pixel type of the image
         * @param renderer the image renderer
         * @param text the text
         * @param x the x-ordinate
         * @param y the y-ordinate
         */
        @SuppressWarnings({ "unchecked", "rawtypes" })
        public static <T> void renderText(ImageRenderer<T,?> renderer, AttributedString text, int x, int y) {
                AttributedCharacterIterator iterator = text.getIterator();
                
                while (true) {
                        Character c = iterator.current();
                        if (c == AttributedCharacterIterator.DONE) break;
                        
                        FontStyle sty = FontStyle.parseAttributes(iterator.getAttributes(), renderer);
                        FontRenderer fontRenderer = sty.getRenderer(renderer);
                        
                        Rectangle rect = fontRenderer.getSize(c.toString(), sty);
                        fontRenderer.renderText(renderer, c.toString(), x, y, sty);
                        x += rect.width;
                        y += rect.height;
                        
                        iterator.next();
                }
        }
        
        /**
         * Calculate the bounding box of the given {@link AttributedString}. The image
         * will not be modified by this call, but is used to properly configure the styles
         * for bounds estimation.
         * 
         * @param <T> the pixel type
         * @param text the text
         * @param imageRenderer the target image renderer
         * @return the bounding box
         */
        @SuppressWarnings({ "rawtypes", "unchecked" })
        public static <T> Rectangle getBounds(AttributedString text, ImageRenderer<T,?> imageRenderer) {
                AttributedCharacterIterator iterator = text.getIterator();
                int x=0, y=0;
                
                while (true) {
                        Character c = iterator.current();
                        if (c == AttributedCharacterIterator.DONE) break;
                        
                        FontStyle sty = FontStyle.parseAttributes(iterator.getAttributes(), imageRenderer);
                        FontRenderer renderer = sty.getRenderer(imageRenderer);
                        
                        Rectangle rect = renderer.getSize(c.toString(), sty);
                        x += rect.width;
                        y += rect.height;
                        
                        iterator.next();
                }
                
                return new Rectangle(0,0,x,y);
        }
}