Java tutorial
/** * Copyright 2010 The PlayN Authors * * 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 playn.html; import com.google.gwt.canvas.dom.client.Context2d; import java.util.ArrayList; import java.util.List; import pythagoras.f.IRectangle; import pythagoras.f.Rectangle; import playn.core.AbstractTextLayout; import playn.core.TextFormat; import static playn.core.PlayN.graphics; class OldHtmlTextLayout extends AbstractTextLayout implements AbstractHtmlCanvas.Drawable { private HtmlFontMetrics metrics; private List<Line> lines = new ArrayList<Line>(); private static class Line { public final String text; public final float width; public Line(String text, float width) { this.text = text; this.width = width; } } OldHtmlTextLayout(Context2d ctx, String text, TextFormat format) { super(text, format); HtmlFont font = getFont(format); this.metrics = ((HtmlGraphics) graphics()).getFontMetrics(font); configContext(ctx); // normalize newlines in the text (Windows: CRLF -> LF, Mac OS pre-X: CR -> LF) text = text.replace("\r\n", "\n").replace('\r', '\n'); if (format.shouldWrap() || text.indexOf('\n') != -1) { for (String line : text.split("\\n")) { String[] words = line.split("\\s"); // TODO: preserve intra-line whitespace for (int idx = 0; idx < words.length;) { // note: measureLine has the side effect of adding the measured line to this.lines and // setting this.width to the maximum of the current width and the measured line width idx = measureLine(ctx, words, idx); } } height = metrics.height * lines.size(); } else { width = (float) ctx.measureText(text).getWidth(); height = metrics.height; lines.add(new Line(text, width)); } // Canvas.measureText does not account for the extra width consumed by italic characters, so we // fudge in a fraction of an em and hope the font isn't too slanted switch (font.style()) { case ITALIC: width += metrics.emwidth / 8; break; case BOLD_ITALIC: width += metrics.emwidth / 6; break; default: break; // nada } } @Override public IRectangle bounds() { return new Rectangle(0, 0, width(), height()); } @Override public int lineCount() { return lines.size(); } @Override public Rectangle lineBounds(int line) { throw new UnsupportedOperationException("Line bounds not supported in HTML backend."); // TODO } @Override public float ascent() { throw new UnsupportedOperationException("Text ascent not supported in HTML backend."); // TODO } @Override public float descent() { throw new UnsupportedOperationException("Text descent not supported in HTML backend."); // TODO } @Override public float leading() { throw new UnsupportedOperationException("Text leading not supported in HTML backend."); // TODO } public void stroke(Context2d ctx, float x, float y) { configContext(ctx); float ypos = 0; for (Line line : lines) { ctx.strokeText(line.text, x + format.align.getX(line.width, width), y + ypos); ypos += metrics.height; } } public void fill(Context2d ctx, float x, float y) { configContext(ctx); float ypos = 0; for (Line line : lines) { ctx.fillText(line.text, x + format.align.getX(line.width, width), y + ypos); ypos += metrics.height; } } void configContext(Context2d ctx) { HtmlFont font = getFont(format); String style = ""; switch (font.style()) { case BOLD: style = "bold"; break; case ITALIC: style = "italic"; break; case BOLD_ITALIC: style = "bold italic"; break; default: break; // nada } ctx.setFont(style + " " + font.size() + "px " + font.name()); ctx.setTextBaseline(Context2d.TextBaseline.TOP); } HtmlFont getFont(TextFormat format) { return format.font == null ? HtmlFont.DEFAULT : (HtmlFont) format.font; } int measureLine(Context2d ctx, String[] words, int idx) { // we always put at least one word on a line String line = words[idx++]; int startIdx = idx; // build a rough estimate line based on character count and emwidth for (; idx < words.length; idx++) { String nline = line + " " + words[idx]; if (nline.length() * metrics.emwidth > format.wrapWidth) break; line = nline; } // now, based on exact measurements, either add more words... double lineWidth = ctx.measureText(line).getWidth(); if (lineWidth < format.wrapWidth) { for (; idx < words.length; idx++) { String nline = line + " " + words[idx]; double nlineWidth = ctx.measureText(nline).getWidth(); if (nlineWidth > format.wrapWidth) break; line = nline; lineWidth = nlineWidth; } } // or pop words off... while (lineWidth > format.wrapWidth && idx > (startIdx + 1)) { // don't pop off the last word line = line.substring(0, line.length() - words[--idx].length() - 1); lineWidth = ctx.measureText(line).getWidth(); } // finally, if we're still over the limit (we have a single looong word), hard break if (lineWidth > format.wrapWidth) { StringBuilder remainder = new StringBuilder(); while (lineWidth > format.wrapWidth && line.length() > 1) { // this could be more efficient, but this edge case should be rare enough not to matter int lastIdx = line.length() - 1; remainder.insert(0, line.charAt(lastIdx)); line = line.substring(0, lastIdx); lineWidth = ctx.measureText(line).getWidth(); } words[--idx] = remainder.toString(); } lines.add(new Line(line, (float) lineWidth)); width = (float) Math.max(width, lineWidth); return idx; } }