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50
51#include "codeeditor.h"
52
53#include <QPainter>
54#include <QTextBlock>
55
56//![constructor]
57
58CodeEditor::CodeEditor(QWidget *parent) : QPlainTextEdit(parent)
59{
60 lineNumberArea = new LineNumberArea(this);
61
62 connect(sender: this, signal: &CodeEditor::blockCountChanged, receiver: this, slot: &CodeEditor::updateLineNumberAreaWidth);
63 connect(sender: this, signal: &CodeEditor::updateRequest, receiver: this, slot: &CodeEditor::updateLineNumberArea);
64 connect(sender: this, signal: &CodeEditor::cursorPositionChanged, receiver: this, slot: &CodeEditor::highlightCurrentLine);
65
66 updateLineNumberAreaWidth(newBlockCount: 0);
67 highlightCurrentLine();
68}
69
70//![constructor]
71
72//![extraAreaWidth]
73
74int CodeEditor::lineNumberAreaWidth()
75{
76 int digits = 1;
77 int max = qMax(a: 1, b: blockCount());
78 while (max >= 10) {
79 max /= 10;
80 ++digits;
81 }
82
83 int space = 3 + fontMetrics().horizontalAdvance(QLatin1Char('9')) * digits;
84
85 return space;
86}
87
88//![extraAreaWidth]
89
90//![slotUpdateExtraAreaWidth]
91
92void CodeEditor::updateLineNumberAreaWidth(int /* newBlockCount */)
93{
94 setViewportMargins(left: lineNumberAreaWidth(), top: 0, right: 0, bottom: 0);
95}
96
97//![slotUpdateExtraAreaWidth]
98
99//![slotUpdateRequest]
100
101void CodeEditor::updateLineNumberArea(const QRect &rect, int dy)
102{
103 if (dy)
104 lineNumberArea->scroll(dx: 0, dy);
105 else
106 lineNumberArea->update(ax: 0, ay: rect.y(), aw: lineNumberArea->width(), ah: rect.height());
107
108 if (rect.contains(r: viewport()->rect()))
109 updateLineNumberAreaWidth(0);
110}
111
112//![slotUpdateRequest]
113
114//![resizeEvent]
115
116void CodeEditor::resizeEvent(QResizeEvent *e)
117{
118 QPlainTextEdit::resizeEvent(e);
119
120 QRect cr = contentsRect();
121 lineNumberArea->setGeometry(QRect(cr.left(), cr.top(), lineNumberAreaWidth(), cr.height()));
122}
123
124//![resizeEvent]
125
126//![cursorPositionChanged]
127
128void CodeEditor::highlightCurrentLine()
129{
130 QList<QTextEdit::ExtraSelection> extraSelections;
131
132 if (!isReadOnly()) {
133 QTextEdit::ExtraSelection selection;
134
135 QColor lineColor = QColor(Qt::yellow).lighter(f: 160);
136
137 selection.format.setBackground(lineColor);
138 selection.format.setProperty(propertyId: QTextFormat::FullWidthSelection, value: true);
139 selection.cursor = textCursor();
140 selection.cursor.clearSelection();
141 extraSelections.append(t: selection);
142 }
143
144 setExtraSelections(extraSelections);
145}
146
147//![cursorPositionChanged]
148
149//![extraAreaPaintEvent_0]
150
151void CodeEditor::lineNumberAreaPaintEvent(QPaintEvent *event)
152{
153 QPainter painter(lineNumberArea);
154 painter.fillRect(r: event->rect(), c: Qt::lightGray);
155
156//![extraAreaPaintEvent_0]
157
158//![extraAreaPaintEvent_1]
159 QTextBlock block = firstVisibleBlock();
160 int blockNumber = block.blockNumber();
161 int top = qRound(d: blockBoundingGeometry(block).translated(p: contentOffset()).top());
162 int bottom = top + qRound(d: blockBoundingRect(block).height());
163//![extraAreaPaintEvent_1]
164
165//![extraAreaPaintEvent_2]
166 while (block.isValid() && top <= event->rect().bottom()) {
167 if (block.isVisible() && bottom >= event->rect().top()) {
168 QString number = QString::number(blockNumber + 1);
169 painter.setPen(Qt::black);
170 painter.drawText(x: 0, y: top, w: lineNumberArea->width(), h: fontMetrics().height(),
171 flags: Qt::AlignRight, str: number);
172 }
173
174 block = block.next();
175 top = bottom;
176 bottom = top + qRound(d: blockBoundingRect(block).height());
177 ++blockNumber;
178 }
179}
180//![extraAreaPaintEvent_2]
181
182

source code of qtbase/examples/widgets/widgets/codeeditor/codeeditor.cpp