// mas964 ps5
// draws phrases along the mouse path, swapping from one to the next.

import java.applet.*;
import java.awt.*;
import java.lang.Math;
import java.lang.String;
import StrokeAnimator;

public class PhraseStroke extends StrokeAnimator {
  Font drawFont;
  FontMetrics dfm;
  String texts[] = {"Iamtheseaofpermutation", "Iamthecrowofdesperation", "Iamtheturmiteoftemptation", "Isenserelentlessvariation"};
  int numColors = 7;
  char textArrays[][];
  int textLengths[];
  int letterYOffset, letterXOffsets[][];
  int numTexts = texts.length;
  Color textColors[];
  boolean swapText;
  int frameNumber;

  // calculate whether to swap letters left/right, reset frame counter
  public boolean mouseUp(Event e, int mouseX, int mouseY) {
    swapText = x[numPoints-1] < x[0];
    frameNumber = 0;
    return super.mouseUp(e, mouseX, mouseY);
  }

  // Draw strings. Note that we ignore the millisecond value entirely,
  // preferring to just use a static frame number.
  public void drawFrame(int ms) {
    if (numPoints <= 0)
      return;

    Graphics g = imageBuffer.getGraphics();
    this.clearImageBuffer();
    g.setFont(drawFont);

    // simple method - just fade in one string, then disappear it.
    if (false) {
      g.setColor(textColors[frameNumber % numColors]);
      drawChars(g, (frameNumber / numColors) % numTexts);
    }
      
    // fancy method - crossfade between words
    if (true) {
      int color1, color2, text1, text2;
      color1 = frameNumber % numColors;
      color2 = numColors - color1 - 1;
      text1 = (frameNumber / numColors + 1) % numTexts;
      text2 = text1 - 1;
      if (text2 < 0)
	text2 = numTexts - 1;

      // draw the darker string last. Would be nice to have alpha...
      if (color1 > numColors / 2) {
	g.setColor(textColors[color2]);
	drawChars(g, text2);
	g.setColor(textColors[color1]);
	drawChars(g, text1);
      } else {
	g.setColor(textColors[color1]);
	drawChars(g, text1);
	g.setColor(textColors[color2]);
	drawChars(g, text2);
      }
    }
    frameNumber++;				  // ignore the time entirely
    repaint(); 
  }

  // this method actually draws the string with the set colour. Each
  // letter is centered on one mouse-event point
  public void drawChars(Graphics g, int textNum) {
    int i, charIndex;

    for (i = 0; i < numPoints; i++) {
      charIndex = i % textLengths[textNum];
      if (swapText)				  // go right to left?
	charIndex = textLengths[textNum] - charIndex - 1;
      g.drawChars(textArrays[textNum], charIndex, 1,
		  x[i] + letterXOffsets[textNum][charIndex],
		  y[i] + letterYOffset);
    }
  }
  
  public void init() {
    int i, j;

    // turn strings into char arrays with lengths
    textArrays = new char[numTexts][];
    textLengths = new int[numTexts];
    for (i = 0; i < numTexts; i++) {
      textArrays[i] = texts[i].toCharArray();
      textLengths[i] = texts[i].length();
    }

    // get the font
    drawFont = new Font("Helvetica", Font.BOLD, 24);
    dfm = getFontMetrics(drawFont);

    // now figure out all the centers for the characters.
    letterYOffset = dfm.getHeight() / 2;
    letterXOffsets = new int[numTexts][];
    for (i = 0; i < numTexts; i++) {
      letterXOffsets[i] = new int[textLengths[i]];
      for (j = 0; j < textLengths[i]; j++) {
	letterXOffsets[i][j] = - dfm.charWidth(textArrays[i][j]) / 2;
      }
    }

    // construct a colourmap - grey sinusoid
    textColors = new Color[numColors];
    textColors[0] = Color.white;
    textColors[1] = new Color(224, 224, 224);
    textColors[2] = new Color(192, 192, 192);
    textColors[3] = new Color(128, 128, 128);
    textColors[4] = new Color(64, 64, 64);
    textColors[5] = new Color(32, 32, 32);
    textColors[6] = Color.black;
    
    this.setBackground(Color.white);
    this.setForeground(Color.black);
    super.init();
    if (frameDelay == 0) {
      frameDelay = 250;
    }
  }
}