Java tutorial
/******************************************************************************* * Copyright (c) 2009, 2016 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.swt.snippets; /* * StyledText: Variable tab stops per line * * For a list of all SWT example snippets see * http://www.eclipse.org/swt/snippets/ * */ import org.eclipse.swt.*; import org.eclipse.swt.custom.*; import org.eclipse.swt.graphics.*; import org.eclipse.swt.layout.*; import org.eclipse.swt.widgets.*; public class Snippet328 { public static void main(String[] args) { Display display = new Display(); Shell shell = new Shell(display); shell.setText("Snippet 328"); shell.setLayout(new GridLayout()); shell.setText("StyledText: Variable tab stops"); Ruler ruler = new Ruler(shell, SWT.NONE); GridData data = new GridData(); data.heightHint = 10; data.horizontalAlignment = SWT.FILL; ruler.setLayoutData(data); ruler.setBackground(display.getSystemColor(SWT.COLOR_INFO_BACKGROUND)); StyledText styledText = new StyledText(shell, SWT.FULL_SELECTION | SWT.BORDER | SWT.H_SCROLL | SWT.V_SCROLL); styledText.setText( "0\t1\t2\t3\t4\nDrag\tthe\ttab\tmarks\ton\ttop\tto\tchange\tthe\tposition\tof\tthe\ttab\tstops"); styledText.setTabStops(new int[] { 30, 70, 90, 140 }); styledText.setLineTabStops(0, 1, new int[] { 10, 60, 80 }); styledText.setLineTabStops(1, 1, new int[] { 40, 70, 100, 150 }); styledText.setLayoutData(new GridData(GridData.FILL_BOTH)); ruler.setEditor(styledText); shell.setSize(800, 400); shell.open(); while (!shell.isDisposed()) { if (!display.readAndDispatch()) display.sleep(); } display.dispose(); } public static class Ruler extends Canvas { StyledText styledText; int hover = -1; int line = 0; public Ruler(Composite parent, int style) { super(parent, style | SWT.DOUBLE_BUFFERED); Display display = getDisplay(); setBackground(display.getSystemColor(SWT.COLOR_INFO_BACKGROUND)); Listener listener = e -> { switch (e.type) { case SWT.Paint: handlePaint(e); break; case SWT.MouseMove: if ((e.stateMask & SWT.BUTTON1) != 0) { handleDragMark(e); } else { handleMouseMove(e); } break; case SWT.MouseExit: if (hover != -1) redraw(); hover = -1; break; } }; addListener(SWT.Paint, listener); addListener(SWT.MouseMove, listener); addListener(SWT.MouseExit, listener); } public void setEditor(StyledText editor) { styledText = editor; styledText.addCaretListener(event -> { int caretLine = styledText.getLineAtOffset(event.caretOffset); if (caretLine != line) { line = caretLine; redraw(); } }); } void handleMouseMove(Event e) { int[] tabs = styledText.getLineTabStops(line); int margin = styledText.getLeftMargin() + styledText.getBorderWidth(); int count = tabs.length; int newIndex = -1; int x = margin; if (x <= e.x && e.x < x + 5) { newIndex = 0; } int i = 0; if (newIndex == -1) { for (i = 0; i < count; i++) { x = tabs[i] + margin; if (x <= e.x && e.x <= x + 5) { newIndex = i + 1; break; } } } if (newIndex == -1) { int lastTabWidth = count > 1 ? tabs[count - 1] - tabs[count - 2] : tabs[0]; x += lastTabWidth; Rectangle ca = getClientArea(); while (x < ca.x + ca.width) { if (x <= e.x && e.x <= x + 5) { newIndex = i + 1; break; } x += lastTabWidth; i++; } } if (newIndex != hover) { hover = newIndex; redraw(); } } void handleDragMark(Event e) { if (hover <= 0) return; int[] tabs = styledText.getLineTabStops(line); int margin = styledText.getLeftMargin() + styledText.getBorderWidth(); int count = tabs.length; int x = e.x - margin; int index = hover - 1; if (index < count) { if (index >= count - 2) { int last = tabs[count - 1]; int secondLast = tabs[count - 2]; int grow = index == count - 1 ? 2 : 1; int[] newTabs = new int[count + grow]; System.arraycopy(tabs, 0, newTabs, 0, count); newTabs[count] = last + (last - secondLast); if (grow == 2) { newTabs[count + 1] = last + 2 * (last - secondLast); } tabs = newTabs; } } else { int[] newTabs = new int[index + 3]; System.arraycopy(tabs, 0, newTabs, 0, count); int last = tabs[count - 1]; int diff = last - tabs[count - 2]; for (int i = count; i < newTabs.length; i++) { newTabs[i] = last + diff; last += diff; } tabs = newTabs; } int min = index > 0 ? tabs[index - 1] + 1 : 0; if (x < min) x = min; int max = tabs[index + 1] - 1; if (x > max) { int diff = x - tabs[index]; for (int i = index + 1; i < count; i++) { tabs[i] += diff; } } tabs[index] = x; styledText.setLineTabStops(line, 1, tabs); redraw(); } void handlePaint(Event e) { Display display = e.display; GC gc = e.gc; int[] tabs = styledText.getLineTabStops(line); int margin = styledText.getLeftMargin() + styledText.getBorderWidth(); int x = margin; gc.setBackground(display.getSystemColor(hover == 0 ? SWT.COLOR_RED : SWT.COLOR_BLACK)); gc.fillPolygon(new int[] { x, 0, x + 5, 0, x, 10 }); int i; for (i = 0; i < tabs.length; i++) { x = tabs[i] + margin; if (x > e.x + e.width) break; gc.setBackground(display.getSystemColor(hover == i + 1 ? SWT.COLOR_RED : SWT.COLOR_BLACK)); gc.fillPolygon(new int[] { x, 0, x + 5, 0, x, 10 }); } int lastTabWidth = tabs.length > 1 ? tabs[tabs.length - 1] - tabs[tabs.length - 2] : tabs[0]; x += lastTabWidth; while (x < e.x + e.width) { gc.setBackground(display.getSystemColor(hover == ++i ? SWT.COLOR_RED : SWT.COLOR_BLACK)); gc.fillPolygon(new int[] { x, 0, x + 5, 0, x, 10 }); x += lastTabWidth; } } } }