QGIS API Documentation 3.39.0-Master (3783037d301)
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qgshtmlwidgetwrapper.cpp
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1/***************************************************************************
2 qgshtmlwidgetwrapper.h
3
4 ---------------------
5 begin : 23.03.2019
6 copyright : (C) 2019 by Alessandro Pasotti
7 email : elpaso at itopen dot it
8 ***************************************************************************
9 * *
10 * This program is free software; you can redistribute it and/or modify *
11 * it under the terms of the GNU General Public License as published by *
12 * the Free Software Foundation; either version 2 of the License, or *
13 * (at your option) any later version. *
14 * *
15 ***************************************************************************/
16
19#include "qgswebframe.h"
21#include "qgsattributeform.h"
22
23#include <QScreen>
24
25QgsHtmlWidgetWrapper::QgsHtmlWidgetWrapper( QgsVectorLayer *layer, QWidget *editor, QWidget *parent )
26 : QgsWidgetWrapper( layer, editor, parent )
27{
28 connect( this, &QgsWidgetWrapper::contextChanged, this, &QgsHtmlWidgetWrapper::setHtmlContext );
29}
30
32{
33 return true;
34}
35
36QWidget *QgsHtmlWidgetWrapper::createWidget( QWidget *parent )
37{
38 QgsAttributeForm *form = qobject_cast<QgsAttributeForm *>( parent );
39
40 if ( form )
41 {
42 mFormFeature = form->feature();
43 connect( form, &QgsAttributeForm::widgetValueChanged, this, [ = ]( const QString & attribute, const QVariant & newValue, bool attributeChanged )
44 {
45 if ( attributeChanged )
46 {
47 if ( mRequiresFormScope )
48 {
49 mFormFeature.setAttribute( attribute, newValue );
50 setHtmlContext();
51 }
52 }
53 } );
54 }
55
56 return new QgsWebView( parent );
57}
58
59void QgsHtmlWidgetWrapper::initWidget( QWidget *editor )
60{
61 mWidget = qobject_cast<QgsWebView *>( editor );
62
63 if ( !mWidget )
64 return;
65
66 mWidget->setHtml( mHtmlCode.replace( "\n", " " ) );
67
68#ifdef WITH_QTWEBKIT
69
70 const int horizontalDpi = mWidget->logicalDpiX();
71
72 mWidget->setZoomFactor( horizontalDpi / 96.0 );
73
74 QWebPage *page = mWidget->page();
75 connect( page, &QWebPage::contentsChanged, this, &QgsHtmlWidgetWrapper::fixHeight, Qt::ConnectionType::UniqueConnection );
76 connect( page, &QWebPage::loadFinished, this, &QgsHtmlWidgetWrapper::fixHeight, Qt::ConnectionType::UniqueConnection );
77
78#endif
79
80 checkGeometryNeeds();
81}
82
84{
85 if ( !mWidget )
86 return;
87
88 initWidget( mWidget );
89}
90
91void QgsHtmlWidgetWrapper::checkGeometryNeeds()
92{
93 if ( !mWidget )
94 return;
95
96 // initialize a temporary QgsWebView to render HTML code and check if one evaluated expression
97 // needs geometry
98 QgsWebView webView;
99 NeedsGeometryEvaluator evaluator;
100
101 const QgsAttributeEditorContext attributecontext = context();
102 if ( QgsVectorLayer *vl = layer() )
103 {
104 const QgsExpressionContext expressionContext = vl->createExpressionContext();
105 evaluator.setExpressionContext( expressionContext );
106 }
107
108 auto frame = webView.page()->mainFrame();
109 connect( frame, &QWebFrame::javaScriptWindowObjectCleared, frame, [ frame, &evaluator ]
110 {
111 frame->addToJavaScriptWindowObject( QStringLiteral( "expression" ), &evaluator );
112 } );
113
114 webView.setHtml( mHtmlCode );
115
116 mNeedsGeometry = evaluator.needsGeometry();
117}
118
119void QgsHtmlWidgetWrapper::setHtmlCode( const QString &htmlCode )
120{
121 mHtmlCode = htmlCode;
122
123 bool ok = false;
124 const thread_local QRegularExpression expRe( QStringLiteral( R"re(expression.evaluate\s*\‍(\s*"(.*)"\))re" ), QRegularExpression::PatternOption::MultilineOption | QRegularExpression::PatternOption::DotMatchesEverythingOption );
125 QRegularExpressionMatchIterator matchIt = expRe.globalMatch( mHtmlCode );
126 while ( !ok && matchIt.hasNext() )
127 {
128 const QRegularExpressionMatch match = matchIt.next();
129 const QgsExpression exp = match.captured( 1 );
131 }
132 mRequiresFormScope = ok;
133
134 checkGeometryNeeds();
135}
136
137void QgsHtmlWidgetWrapper::setHtmlContext( )
138{
139 if ( !mWidget )
140 return;
141
142 const QgsAttributeEditorContext attributecontext = context();
143 QgsExpressionContext expressionContext = layer()->createExpressionContext();
144 expressionContext << QgsExpressionContextUtils::formScope( mFormFeature, attributecontext.attributeFormModeString() );
145 if ( attributecontext.parentFormFeature().isValid() )
146 {
147 expressionContext << QgsExpressionContextUtils::parentFormScope( attributecontext.parentFormFeature() );
148 }
149
150 expressionContext.setFeature( mFeature );
151
152 HtmlExpression *htmlExpression = new HtmlExpression();
153 htmlExpression->setExpressionContext( expressionContext );
154 auto frame = mWidget->page()->mainFrame();
155 connect( frame, &QWebFrame::javaScriptWindowObjectCleared, frame, [ = ]
156 {
157 frame->addToJavaScriptWindowObject( QStringLiteral( "expression" ), htmlExpression );
158 } );
159
160 mWidget->setHtml( mHtmlCode );
161}
162
163#ifdef WITH_QTWEBKIT
164void QgsHtmlWidgetWrapper::fixHeight()
165{
166 QWebPage *page = mWidget->page();
167 const int docHeight { page->mainFrame()->contentsSize().height() };
168 mWidget->setFixedHeight( docHeight );
169}
170#endif
171
173{
174 if ( !mWidget )
175 return;
176
177 mFeature = feature;
178 mFormFeature = feature;
179 setHtmlContext();
180}
181
183{
184 return mNeedsGeometry;
185}
186
187
189void HtmlExpression::setExpressionContext( const QgsExpressionContext &context )
190{
191 mExpressionContext = context;
192}
193
194QString HtmlExpression::evaluate( const QString &expression ) const
195{
196 QgsExpression exp { expression };
197 exp.prepare( &mExpressionContext );
198 return exp.evaluate( &mExpressionContext ).toString();
199}
200
201void NeedsGeometryEvaluator::evaluate( const QString &expression )
202{
203 QgsExpression exp { expression };
204 exp.prepare( &mExpressionContext );
205 mNeedsGeometry |= exp.needsGeometry();
206}
207
208void NeedsGeometryEvaluator::setExpressionContext( const QgsExpressionContext &context )
209{
210 mExpressionContext = context;
211}
212
213
The QWebPage class is a collection of stubs to mimic the API of a QWebPage on systems where QtWebkit ...
Definition qgswebpage.h:104
This class contains context information for attribute editor widgets.
QString attributeFormModeString() const
Returns given attributeFormMode as string.
QgsFeature parentFormFeature() const
Returns the feature of the currently edited parent form in its actual state.
void widgetValueChanged(const QString &attribute, const QVariant &value, bool attributeChanged)
Notifies about changes of attributes.
const QgsFeature & feature()
static QgsExpressionContextScope * parentFormScope(const QgsFeature &formFeature=QgsFeature(), const QString &formMode=QString())
Creates a new scope which contains functions and variables from the current parent attribute form/tab...
static QgsExpressionContextScope * formScope(const QgsFeature &formFeature=QgsFeature(), const QString &formMode=QString())
Creates a new scope which contains functions and variables from the current attribute form/table form...
Expression contexts are used to encapsulate the parameters around which a QgsExpression should be eva...
void setFeature(const QgsFeature &feature)
Convenience function for setting a feature for the context.
Class for parsing and evaluation of expressions (formerly called "search strings").
bool prepare(const QgsExpressionContext *context)
Gets the expression ready for evaluation - find out column indexes.
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Definition qgsfeature.h:58
Q_INVOKABLE bool setAttribute(int field, const QVariant &attr)
Sets an attribute's value by field index.
bool isValid() const
Returns the validity of this feature.
void reinitWidget()
Clears the content and makes new initialization.
void initWidget(QWidget *editor) override
This method should initialize the editor widget with runtime data.
QWidget * createWidget(QWidget *parent) override
This method should create a new widget with the provided parent.
QgsHtmlWidgetWrapper(QgsVectorLayer *layer, QWidget *editor, QWidget *parent)
Create a html widget wrapper.
void setHtmlCode(const QString &htmlCode)
Sets the HTML code to htmlCode.
bool valid() const override
Returns true if the widget has been properly initialized.
void setFeature(const QgsFeature &feature) override
bool needsGeometry() const
Returns true if the widget needs feature geometry.
static bool expressionRequiresFormScope(const QString &expression)
Check if the expression requires a form scope (i.e.
Represents a vector layer which manages a vector based data sets.
QgsExpressionContext createExpressionContext() const FINAL
This method needs to be reimplemented in all classes which implement this interface and return an exp...
The QgsWebView class is a collection of stubs to mimic the API of QWebView on systems where the real ...
Definition qgswebview.h:66
Manages an editor widget Widget and wrapper share the same parent.
void contextChanged()
Signal when QgsAttributeEditorContext mContext changed.
const QgsAttributeEditorContext & context() const
Returns information about the context in which this widget is shown.
QgsVectorLayer * layer() const
Returns the vector layer associated with the widget.