1qwtchangelog(3) Qwt User's Guide qwtchangelog(3)
2
6 qwtchangelog - What's new in Qwt 6.1
7
10 · QwtPlotBarChart
11 Bar chart, see 'examples/distrowatch'
12 · QwtPlotMultiBarChart
14 Chart of grouped bars - stacked or aligned side by side. See
15 'examples/barchart'
16 · QwtPlotTradingCurve
18 Candlestick or OHLC charts typically used to describe price
19 movements over time. See 'examples/stockchart'
20 · QwtPlotShapeItem
22 A plot item to display rectangles, circles, polygons and all other
23 type of shapes ( built from intersections or unifications ), that can
24 be expressed by a QPainterPath. See 'examples/itemeditor'
25 · QwtPlotLegendItem
27 A legend on the plot canvas. See 'examples/legends'
28 · QwtPlotZoneItem
30 A horizontal or vertical section
31 · QwtPlotTextLabel
33 In opposite to a QwtPlotMarker the text is not aligned to a plot
34 coordinate but according to the geometry of the canvas ( f.e
35 top/centered for a title ). See 'playground/curvetracker'.
36
38 QwtScaleTransformation has been replaced by QwtTransform and its
39 derived classes:
40 · QwtTransform
42 · QwtNullTransform
44 · QwtLogTransform
46 · QwtPowerTransform
48 Individual transformations ( f.e. different scaling for special
50 sections ) can be implemented by overloading QwtTransform ( see
51 playground/scaleengine ).
52 QwtLinearScaleEngine and QwtLogScaleEngine are not limited to base 10
54 anymore.
55 Datetime scales
57 A set of a new classes for displaying datetime values:
58 · QwtDate
60 A collection of methods to convert between QDateTime and doubles
61 · QwtDateScaleEngine
63 A scale engine that aligns and finds ticks in terms of datetime
64 units.
65 · QwtDateScaleDraw
67 A scale draw mapping values to datetime strings.
68 Scales for Qt::UTC and Qt::LocalTime are supported.
70
72 Many parts of the class design of the dial and meter widgets were left
73 over from the 90s ( Qwt 0.2, Qt 1.1 ).
74 The derivation tree is simpler and more logical:
76 · QwtAbstractScale is a QWidget
78 · QwtAbstractSlider is a QwtAbstractScale. ( for sliders without scales
80 QAbstractSlider should be the base class )
81 · QwtThermo is also a QwtAbstractScale
83 · QwtDial, QwtKnob, QwtSlider are derived from QwtAbstractSlider
85 · QwtCounter is derived from QWidget
87 QwtDoubleRange has been removed.
89 All classes use the terminology known from QAbstractSlider - as far as
91 possible. The extended system for scales is completely supported.
92
94 QwtPlotGLCanvas offers the option to draw plot items using an OpenGL
95 paint engine ( QPaintEngine::OpenGL/OpenGL2 ), This is not what could
96 be implemented with native OpenGL, but it offers hardware acceleration
97 in environments, where the raster paint engine is the only option. (
98 f.e Qt4/Windows, or Qt5 on all platforms ).
99 QwtPlotGLCanvas is in an experimental state and is not recommended for
101 average use cases.
102
104 QwtLegend has been decoupled from QwtPlot and can be replaced by
105 application specific implementations. Plot items and the legend
106 exchange the information using QwtLegendData.
107 QwtPlotLegendItem is a new plot item that displays a legend on the plot
109 canvas.
110 The following examples demonstrate how to use the new system:
112 · examples/legends
114 shows how to use the new legend system
115 · examples/stockchart
117 implementats a QTreeView with checkable items as legend
118
120 QwtGraphic can be copied like QImage or QPixmap but is scalable like
121 QSvgGenerator. It is implemented as a record/replay paint device like
122 QPicture.
123
125 QwtWidgetOverlay is a base class for implementing widget overlays -
126 primarily used for use cases like graphical editors or running cursors
127 for the plot canvas.
128 The following examples show how to use overlays:
130 · examples/itemeditor
132 · examples/curvetracker
134 QwtPicker ( -> QwtPlotPicker, QwtPlotZoomer ) internally uses
136 QwtWidgetOverlay now, making it easier to implement individual rubber
137 bands.
138
140 New symbol types have been introduced:
141 · QwtSymbol::Path
143 · QwtSymbol::Pixmap
145 · QwtSymbol::Graphic
147 · QwtSymbol::SvgDocument
149 QwtSymbol autodetect the most performant paint strategy for a paint
151 device what is in most situations using a QPixmap cache.
152 QwtSymbol::setPinPoint() allows to align the symbol individually, f.e
154 to the position of the peak of an arrow.
155
157 Some optimizations that got lost with introducing the floating point
158 based render code with Qwt 6.0 have been reenabled. Other specific
159 optimizations have been added.
160 New paint attributes:
162 · QwtPlotCurve::FilterPoints
164 · QwtPlotCurve::MinimizeMemory
166 · QwtPlotCurve::ImageBuffer
168 QwtPlotCurve::CacheSymbols has been removed, as caching is implemented
170 in QwtSymbol now.
171 QwtPlotCurve::drawLines(), QwtPlotCurve::drawDots(),
172 QwtPlotCurve::drawSteps() and QwtPlotCurve::drawSticks() are virtual
173 now.
174
176 A footer similar to a title has been added.
177 QwtPlot::ExternalLegend is obsolete with the new system for legends.
179 The signals QwtPlot::legendClicked(), QwtPlot::legendChecked() have
180 been removed. Applications need to connect to QwtLegend::clicked() and
181 QwtLegend::checked().
182 To support using an OpenGL canvas QwtPlot::setCanvas has been added.
184 This has 2 important implications for the application code:
185 · QwtPlot::canvas() returns QWidget and needs to be casted, when using
187 methods of QwtPlotCanvas.
188 · QwtPlotCanvas can be created and assigned in application code, what
190 makes it possible to derive and overload methods.
191 The initialization of a plot canvas with Qwt 6.1 will probably look
193 like this:
194 QwtPlotCanvas* canvas = new QwtPlotCanvas();
196 canvas->setXY( ... );
197 ...
198 plot->setCanvas( canvas );
200 To have a consistent API QwtPlot::setPlotLayout() has been added,
202
204 QwtScaleDiv
205 The following methods have been added:
206 · QwtScaleDiv::inverted()
208 · QwtScaleDiv::bounded()
210 · QwtScaleDiv::isEmpty()
212 · QwtScaleDiv::isIncreasing()
214 · QDebug operator
216 The following methods have been removed:
218 · QwtScaleDiv::isValid(), QwtScaleDiv::invalidate()
220 The valid state was left over from early Qwt versions indicating a
221 state of the autoscaler.
222 QwtScaleEngine
224 The following methods have been added:
225 · QwtScaleEngine::setBase()
227 · QwtScaleEngine::setTransformation()
229 QwtPlotLayout
231 The following flags have been added:
232 · QwtPlotLayout::IgnoreTitle
234 · QwtPlotLayout::IgnoreFooter
236 · QwtPlotLayout::setAlignCanvasToScale()
238 QwtPlotCanvas
240 Rounded borders ( like with style sheets ) can configured using
241 QwtPlotCanvas::setBorderRadius();
242 Other changes
244 · QwtWeedingCurveFitter
245 QwtWeedingCurveFitter::setChunkSize() has been added, with drastic
246 performance improvements for huge sets of points.
247 · QwtPlotRenderer The frame of the plot canvas can be rendered, what
249 makes the result even closer to WYSWYG. QwtPlotRenderer::exportTo()
250 has been added.
251 · QwtSystemClock For Qt >= 4.9 QwtSystemClock uses QElapsedTimer
253 internally. As it doesn't support a similar feature,
254 QwtSystemClock::precision() has been removed.
255 · QwtPlotAbstractSeriesItem
257 QwtPlotAbstractSeriesItem has been split into QwtPlotSeriesItem and
258 QwtPlotAbstractSeriesStore.
259 · QwtText
261 A metatype declaration has been added, so that QwtText can be used
262 with QVariant.
263 · QwtEventPattern, QwtPanner, QwtMagnifier
265 Forgotten Qt3 leftovers have been fixed: int ->
266 Qt::KeyboardModifiers
267 · QPen Qt5/Qt4 incompatibility The default pen width for Qt5 is 1, what
269 makes it a non cosmetic. To hide this nasty incompatibility several
270 setPen() methods have been added the build pens with a width 0. See
271 QPen::isCosmetic(),
272 · qwtUpperSampleIndex()
274 A binary search algorithm for sorted samples
275 · QwtMatrixRasterData QwtMatrixRasterData::setValue() has been added
277 · QwtPicker QwtPicker::rubberBandWidget(), QwtPicker::trackerWidget()
279 have been replaced by QwtPicker::rubberBandOverlay(),
280 QwtPicker::trackerOverlay(). QwtPicker::rubberBandMask() has been
281 added. QwtPicker::pickRect() has been replaced by
282 QwtPicker::pickArea()
283 · QwtPlotItem QwtPlotItem::ItemInterest has been added.
285 QwtPlotItem::setRenderThreadCount() was shifted from
286 QwtPlotRasterItem.
287 · ...
289
291 · QwtAbstractLegend
292 · QwtDate
294 · QwtDateScaleDraw
296 · QwtDateScaleEngine
298 · QwtGraphic
300 · QwtLegendData
302 · QwtLegendLabel
304 · QwtPainterCommand
306 · QwtPixelMatrix
308 · QwtPlotAbstractBarChart
310 · QwtPlotBarChart
312 · QwtPlotMultiBarChart
314 · QwtPlotGLCanvas
316 · QwtPlotLegendItem
318 · QwtPlotShapeItem
320 · QwtPlotTextLabel
322 · QwtPlotTradingCurve
324 · QwtPlotZoneItem
326 · QwtPointData
328 · QwtPointMapper
330 · QwtTransform, QwtNullTransform, QwtLogTransform, QwtPowerTransform
332 · QwtWidgetOverlay
334Version 6.1.4 Wed Jan 2 2019 qwtchangelog(3)