content: /*
   * Copyright 2019 FormDev Software GmbH
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package themeengine.include.com.formdev.flatlaf.util;
  
  import java.awt.Graphics;
  import java.awt.Graphics2D;
  import java.awt.font.GlyphVector;
  import java.awt.geom.AffineTransform;
  import java.awt.geom.Rectangle2D;
  import java.text.AttributedCharacterIterator;
  import javax.swing.JComponent;
  import themeengine.include.com.formdev.flatlaf.FlatSystemProperties;
  
  /**
   * @author Karl Tauber
   */
  public class HiDPIUtils
  {
  	public interface Painter {
  		public void paint( Graphics2D g, int x, int y, int width, int height, double scaleFactor );
  	}
  
  	public static void paintAtScale1x( Graphics2D g, JComponent c, Painter painter ) {
  		paintAtScale1x( g, 0, 0, c.getWidth(), c.getHeight(), painter );
  	}
  
  	/**
  	 * Paint at system scale factor 1x to avoid rounding issues at 125%, 150% and 175% scaling.
  	 * <p>
  	 * Scales the given Graphics2D down to 100% and invokes the
  	 * given painter passing scaled x, y, width and height.
  	 * <p>
  	 * Uses the same scaling calculation as the JRE uses.
  	 */
  	public static void paintAtScale1x( Graphics2D g, int x, int y, int width, int height, Painter painter ) {
  		// save original transform
  		AffineTransform transform = g.getTransform();
  
  		// check whether scaled
  		if( transform.getScaleX() == 1 && transform.getScaleY() == 1 ) {
  			painter.paint( g, x, y, width, height, 1 );
  			return;
  		}
  
  		// scale rectangle
  		Rectangle2D.Double scaledRect = scale( transform, x, y, width, height );
  
  		try {
  			// unscale to factor 1.0 and move origin (to whole numbers)
  			g.setTransform( new AffineTransform( 1, 0, 0, 1,
  				Math.floor( scaledRect.x ), Math.floor( scaledRect.y ) ) );
  
  			int swidth = (int) scaledRect.width;
  			int sheight = (int) scaledRect.height;
  
  			// paint
  			painter.paint( g, 0, 0, swidth, sheight, transform.getScaleX() );
  		} finally {
  			// restore original transform
  			g.setTransform( transform );
  		}
  	}
  
  	/**
  	 * Scales a rectangle in the same way as the JRE does in
  	 * sun.java2d.pipe.PixelToParallelogramConverter.fillRectangle(),
  	 * which is used by Graphics.fillRect().
  	 */
  	private static Rectangle2D.Double scale( AffineTransform transform, int x, int y, int width, int height ) {
  		double dx1 = transform.getScaleX();
  		double dy2 = transform.getScaleY();
  		double px = x * dx1 + transform.getTranslateX();
  		double py = y * dy2 + transform.getTranslateY();
  		dx1 *= width;
  		dy2 *= height;
  
  		double newx = normalize( px );
  		double newy = normalize( py );
  		dx1 = normalize( px + dx1 ) - newx;
  		dy2 = normalize( py + dy2 ) - newy;
  
  		return new Rectangle2D.Double( newx, newy, dx1, dy2 );
  	}
  
  	private static double normalize( double value ) {
  		return Math.floor( value + 0.25 ) + 0.25;
  	}
  
  
  	private static Boolean useTextYCorrection;
  
  	private static boolean useTextYCorrection() {
  		if( useTextYCorrection == null )
  			useTextYCorrection = FlatSystemProperties.getBoolean( FlatSystemProperties.USE_TEXT_Y_CORRECTION, true );
  		return useTextYCorrection;
  	}
  
  	/**
  	 * When painting text on HiDPI screens and the JRE scales, then the text is
  	 * painted too far down on some operating systems.
  	 * The higher the system scale factor is, the more.
  	 * <p>
  	 * This methods computes a correction value for the Y position.
  	 */
  	public static float computeTextYCorrection( Graphics2D g ) {
  		if( !useTextYCorrection() || !SystemInfo.isWindows )
  			return 0;
  
  		if( !SystemInfo.isJava_9_orLater )
  			return UIScale.getUserScaleFactor() > 1 ? -UIScale.scale( 0.625f ) : 0;
  
  		AffineTransform t = g.getTransform();
  		double scaleY = t.getScaleY();
  		if( scaleY < 1.25 )
  			return 0;
  
  		// Text is painted at slightly different Y positions depending on scale factor
  		// and Y position of component.
  		// The exact reason is not yet known (to me), but there are several factors:
  		// - fractional scale factors result in fractional component Y device coordinates
  		// - fractional text Y device coordinates are rounded for horizontal lines of characters
  		// - maybe different rounding methods for drawing primitives (e.g. rectangle) and text
  		// - Java adds 0.5 to X/Y positions in before drawing string in BufferedTextPipe.enqueueGlyphList()
  
  		// this is not the optimal solution, but works very good in most cases
  		// (tested with class FlatPaintingStringTest on Windows 10 with font "Segoe UI")
  		if( scaleY <= 1.25 )
  			return -0.875f;
  		if( scaleY <= 1.5 )
  			return -0.625f;
  		if( scaleY <= 1.75 )
  			return -0.875f;
  		if( scaleY <= 2.0 )
  			return -0.75f;
  		if( scaleY <= 2.25 )
  			return -0.875f;
  		if( scaleY <= 3.5 )
  			return -0.75f;
  		return -0.875f;
  	}
  
  	/**
  	 * Applies Y correction and draws the given string at the specified location.
  	 * The provided component is used to query text properties and anti-aliasing hints.
  	 * <p>
  	 * Use this method instead of {@link Graphics#drawString(String, int, int)} for correct anti-aliasing.
  	 * <p>
  	 * Replacement for {@code SwingUtilities2.drawString()}.
  	 */
  	public static void drawStringWithYCorrection( JComponent c, Graphics2D g, String text, int x, int y ) {
  		drawStringUnderlineCharAtWithYCorrection( c, g, text, -1, x, y );
  	}
  
  	/**
  	 * Applies Y correction and draws the given string at the specified location underlining the specified character.
  	 * The provided component is used to query text properties and anti-aliasing hints.
  	 * <p>
  	 * Replacement for {@code SwingUtilities2.drawStringUnderlineCharAt()}.
  	 */
  	public static void drawStringUnderlineCharAtWithYCorrection( JComponent c,
  		Graphics2D g, String text, int underlinedIndex, int x, int y )
  	{
  		float yCorrection = computeTextYCorrection( g );
  		if( yCorrection != 0 ) {
  			g.translate( 0, yCorrection );
  			JavaCompatibility.drawStringUnderlineCharAt( c, g, text, underlinedIndex, x, y );
  			g.translate( 0, -yCorrection );
  		} else
  			JavaCompatibility.drawStringUnderlineCharAt( c, g, text, underlinedIndex, x, y );
  	}
  
  	/**
  	 * Creates a graphics object and applies Y correction to string drawing methods.
  	 * If no Y correction is necessary, the passed in graphics object is returned.
  	 */
  	public static Graphics2D createGraphicsTextYCorrection( Graphics2D g ) {
  		float yCorrection = computeTextYCorrection( g );
  		if( yCorrection == 0 )
  			return g;
  
  		return new Graphics2DProxy( g ) {
  			@Override
  			public void drawString( String str, int x, int y ) {
  				super.drawString( str, x, y + yCorrection );
  			}
  
  			@Override
  			public void drawString( String str, float x, float y ) {
  				super.drawString( str, x, y + yCorrection );
  			}
  
  			@Override
  			public void drawString( AttributedCharacterIterator iterator, int x, int y ) {
  				super.drawString( iterator, x, y + yCorrection );
  			}
  
  			@Override
  			public void drawString( AttributedCharacterIterator iterator, float x, float y ) {
  				super.drawString( iterator, x, y + yCorrection );
  			}
  
  			@Override
  			public void drawChars( char[] data, int offset, int length, int x, int y ) {
  				super.drawChars( data, offset, length, x, Math.round( y + yCorrection ) );
  			}
  
  			@Override
  			public void drawBytes( byte[] data, int offset, int length, int x, int y ) {
  				super.drawBytes( data, offset, length, x, Math.round( y + yCorrection ) );
  			}
  
  			@Override
  			public void drawGlyphVector( GlyphVector g, float x, float y ) {
  				super.drawGlyphVector( g, x, y + yCorrection );
  			}
  		};
  	}
  }
  