source: trunk/doc/html/qwmatrix.html@ 203

Last change on this file since 203 was 190, checked in by rudi, 14 years ago

reference documentation added
File size: 24.5 KB
Line 
1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
2<!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/src/kernel/qwmatrix.cpp:51 -->
3<html>
4<head>
5<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
6<title>QWMatrix Class</title>
7<style type="text/css"><!--
8fn { margin-left: 1cm; text-indent: -1cm; }
9a:link { color: #004faf; text-decoration: none }
10a:visited { color: #672967; text-decoration: none }
11body { background: #ffffff; color: black; }
12--></style>
13</head>
14<body>
15
16<table border="0" cellpadding="0" cellspacing="0" width="100%">
17<tr bgcolor="#E5E5E5">
18<td valign=center>
19 <a href="index.html">
20<font color="#004faf">Home</font></a>
21 | <a href="classes.html">
22<font color="#004faf">All&nbsp;Classes</font></a>
23 | <a href="mainclasses.html">
24<font color="#004faf">Main&nbsp;Classes</font></a>
25 | <a href="annotated.html">
26<font color="#004faf">Annotated</font></a>
27 | <a href="groups.html">
28<font color="#004faf">Grouped&nbsp;Classes</font></a>
29 | <a href="functions.html">
30<font color="#004faf">Functions</font></a>
31</td>
32<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>QWMatrix Class Reference</h1>
33
34<p>The QWMatrix class specifies 2D transformations of a
35coordinate system.
36<a href="#details">More...</a>
37<p><tt>#include &lt;<a href="qwmatrix-h.html">qwmatrix.h</a>&gt;</tt>
38<p><a href="qwmatrix-members.html">List of all member functions.</a>
39<h2>Public Members</h2>
40<ul>
41<li class=fn><a href="#QWMatrix"><b>QWMatrix</b></a> ()</li>
42<li class=fn><a href="#QWMatrix-2"><b>QWMatrix</b></a> ( double&nbsp;m11, double&nbsp;m12, double&nbsp;m21, double&nbsp;m22, double&nbsp;dx, double&nbsp;dy )</li>
43<li class=fn>void <a href="#setMatrix"><b>setMatrix</b></a> ( double&nbsp;m11, double&nbsp;m12, double&nbsp;m21, double&nbsp;m22, double&nbsp;dx, double&nbsp;dy )</li>
44<li class=fn>double <a href="#m11"><b>m11</b></a> () const</li>
45<li class=fn>double <a href="#m12"><b>m12</b></a> () const</li>
46<li class=fn>double <a href="#m21"><b>m21</b></a> () const</li>
47<li class=fn>double <a href="#m22"><b>m22</b></a> () const</li>
48<li class=fn>double <a href="#dx"><b>dx</b></a> () const</li>
49<li class=fn>double <a href="#dy"><b>dy</b></a> () const</li>
50<li class=fn>void <a href="#map"><b>map</b></a> ( int&nbsp;x, int&nbsp;y, int&nbsp;*&nbsp;tx, int&nbsp;*&nbsp;ty ) const</li>
51<li class=fn>void <a href="#map-2"><b>map</b></a> ( double&nbsp;x, double&nbsp;y, double&nbsp;*&nbsp;tx, double&nbsp;*&nbsp;ty ) const</li>
52<li class=fn>QRect <a href="#mapRect"><b>mapRect</b></a> ( const&nbsp;QRect&nbsp;&amp;&nbsp;rect ) const</li>
53<li class=fn>QPoint <a href="#map-3"><b>map</b></a> ( const&nbsp;QPoint&nbsp;&amp;&nbsp;p ) const</li>
54<li class=fn>QRect map ( const&nbsp;QRect&nbsp;&amp;&nbsp;r ) const &nbsp;<em>(obsolete)</em></li>
55<li class=fn>QPointArray <a href="#map-5"><b>map</b></a> ( const&nbsp;QPointArray&nbsp;&amp;&nbsp;a ) const</li>
56<li class=fn>QRegion <a href="#map-6"><b>map</b></a> ( const&nbsp;QRegion&nbsp;&amp;&nbsp;r ) const</li>
57<li class=fn>QRegion <a href="#mapToRegion"><b>mapToRegion</b></a> ( const&nbsp;QRect&nbsp;&amp;&nbsp;rect ) const</li>
58<li class=fn>QPointArray <a href="#mapToPolygon"><b>mapToPolygon</b></a> ( const&nbsp;QRect&nbsp;&amp;&nbsp;rect ) const</li>
59<li class=fn>void <a href="#reset"><b>reset</b></a> ()</li>
60<li class=fn>bool <a href="#isIdentity"><b>isIdentity</b></a> () const</li>
61<li class=fn>QWMatrix &amp; <a href="#translate"><b>translate</b></a> ( double&nbsp;dx, double&nbsp;dy )</li>
62<li class=fn>QWMatrix &amp; <a href="#scale"><b>scale</b></a> ( double&nbsp;sx, double&nbsp;sy )</li>
63<li class=fn>QWMatrix &amp; <a href="#shear"><b>shear</b></a> ( double&nbsp;sh, double&nbsp;sv )</li>
64<li class=fn>QWMatrix &amp; <a href="#rotate"><b>rotate</b></a> ( double&nbsp;a )</li>
65<li class=fn>bool <a href="#isInvertible"><b>isInvertible</b></a> () const</li>
66<li class=fn>double <a href="#det"><b>det</b></a> () const</li>
67<li class=fn>QWMatrix <a href="#invert"><b>invert</b></a> ( bool&nbsp;*&nbsp;invertible = 0 ) const</li>
68<li class=fn>bool <a href="#operator-eq-eq"><b>operator==</b></a> ( const&nbsp;QWMatrix&nbsp;&amp;&nbsp;m ) const</li>
69<li class=fn>bool <a href="#operator!-eq"><b>operator!=</b></a> ( const&nbsp;QWMatrix&nbsp;&amp;&nbsp;m ) const</li>
70<li class=fn>QWMatrix &amp; <a href="#operator*-eq"><b>operator*=</b></a> ( const&nbsp;QWMatrix&nbsp;&amp;&nbsp;m )</li>
71<li class=fn>enum <a href="#TransformationMode-enum"><b>TransformationMode</b></a> { Points, Areas }</li>
72</ul>
73<h2>Static Public Members</h2>
74<ul>
75<li class=fn>void <a href="#setTransformationMode"><b>setTransformationMode</b></a> ( QWMatrix::TransformationMode&nbsp;m )</li>
76<li class=fn>TransformationMode <a href="#transformationMode"><b>transformationMode</b></a> ()</li>
77</ul>
78<h2>Related Functions</h2>
79<ul>
80<li class=fn>QDataStream &amp; <a href="#operator-lt-lt"><b>operator&lt;&lt;</b></a> ( QDataStream&nbsp;&amp;&nbsp;s, const&nbsp;QWMatrix&nbsp;&amp;&nbsp;m )</li>
81<li class=fn>QDataStream &amp; <a href="#operator-gt-gt"><b>operator&gt;&gt;</b></a> ( QDataStream&nbsp;&amp;&nbsp;s, QWMatrix&nbsp;&amp;&nbsp;m )</li>
82</ul>
83<hr><a name="details"></a><h2>Detailed Description</h2>
84
85
86The QWMatrix class specifies 2D transformations of a
87coordinate system.
88<p>
89
90<p> The standard coordinate system of a <a href="qpaintdevice.html">paint
91 device</a> has the origin located at the top-left position. X
92values increase to the right; Y values increase downward.
93<p> This coordinate system is the default for the <a href="qpainter.html">QPainter</a>, which
94renders graphics in a paint device. A user-defined coordinate
95system can be specified by setting a QWMatrix for the painter.
96<p> Example:
97<pre>
98 MyWidget::paintEvent( <a href="qpaintevent.html">QPaintEvent</a> * )
99 {
100 <a href="qpainter.html">QPainter</a> p; // our painter
101 QWMatrix m; // our transformation matrix
102 m.<a href="#rotate">rotate</a>( 22.5 ); // rotated coordinate system
103 p.<a href="qpainter.html#begin">begin</a>( this ); // start painting
104 p.<a href="qpainter.html#setWorldMatrix">setWorldMatrix</a>( m ); // use rotated coordinate system
105 p.<a href="qpainter.html#drawText">drawText</a>( 30,20, "detator" ); // draw rotated text at 30,20
106 p.<a href="qpainter.html#end">end</a>(); // painting done
107 }
108 </pre>
109
110<p> A matrix specifies how to translate, scale, shear or rotate the
111graphics; the actual transformation is performed by the drawing
112routines in <a href="qpainter.html">QPainter</a> and by <a href="qpixmap.html#xForm">QPixmap::xForm</a>().
113<p> The QWMatrix class contains a 3x3 matrix of the form:
114<table align=center border=1 cellpadding=1 cellspacing=0>
115<tr align=center><td>m11</td><td>m12</td><td>&nbsp;0 </td></tr>
116<tr align=center><td>m21</td><td>m22</td><td>&nbsp;0 </td></tr>
117<tr align=center><td>dx</td> <td>dy</td> <td>&nbsp;1 </td></tr>
118</table>
119<p> A matrix transforms a point in the plane to another point:
120<pre>
121 x' = m11*x + m21*y + dx
122 y' = m22*y + m12*x + dy
123 </pre>
124
125<p> The point <em>(x, y)</em> is the original point, and <em>(x', y')</em> is the
126transformed point. <em>(x', y')</em> can be transformed back to <em>(x, y)</em> by performing the same operation on the <a href="#invert">inverted matrix</a>.
127<p> The elements <em>dx</em> and <em>dy</em> specify horizontal and vertical
128translation. The elements <em>m11</em> and <em>m22</em> specify horizontal and
129vertical scaling. The elements <em>m12</em> and <em>m21</em> specify
130horizontal and vertical shearing.
131<p> The identity matrix has <em>m11</em> and <em>m22</em> set to 1; all others are
132set to 0. This matrix maps a point to itself.
133<p> Translation is the simplest transformation. Setting <em>dx</em> and <em>dy</em> will move the coordinate system <em>dx</em> units along the X axis
134and <em>dy</em> units along the Y axis.
135<p> Scaling can be done by setting <em>m11</em> and <em>m22</em>. For example,
136setting <em>m11</em> to 2 and <em>m22</em> to 1.5 will double the height and
137increase the width by 50%.
138<p> Shearing is controlled by <em>m12</em> and <em>m21</em>. Setting these
139elements to values different from zero will twist the coordinate
140system.
141<p> Rotation is achieved by carefully setting both the shearing
142factors and the scaling factors. The QWMatrix also has a function
143that sets <a href="#rotate">rotation</a> directly.
144<p> QWMatrix lets you combine transformations like this:
145<pre>
146 QWMatrix m; // identity matrix
147 m.<a href="#translate">translate</a>(10, -20); // first translate (10,-20)
148 m.<a href="#rotate">rotate</a>(25); // then rotate 25 degrees
149 m.<a href="#scale">scale</a>(1.2, 0.7); // finally scale it
150 </pre>
151
152<p> Here's the same example using basic matrix operations:
153<pre>
154 double a = pi/180 * 25; // convert 25 to radians
155 double sina = sin(a);
156 double cosa = cos(a);
157 QWMatrix m1(1, 0, 0, 1, 10, -20); // translation matrix
158 QWMatrix m2( cosa, sina, // rotation matrix
159 -sina, cosa, 0, 0 );
160 QWMatrix m3(1.2, 0, 0, 0.7, 0, 0); // scaling matrix
161 QWMatrix m;
162 m = m3 * m2 * m1; // combine all transformations
163 </pre>
164
165<p> <a href="qpainter.html">QPainter</a> has functions to translate, scale, shear and rotate the
166coordinate system without using a QWMatrix. Although these
167functions are very convenient, it can be more efficient to build a
168QWMatrix and call <a href="qpainter.html#setWorldMatrix">QPainter::setWorldMatrix</a>() if you want to perform
169more than a single transform operation.
170<p> <p>See also <a href="qpainter.html#setWorldMatrix">QPainter::setWorldMatrix</a>(), <a href="qpixmap.html#xForm">QPixmap::xForm</a>(), <a href="graphics.html">Graphics Classes</a>, and <a href="images.html">Image Processing Classes</a>.
171
172<hr><h2>Member Type Documentation</h2>
173<h3 class=fn><a name="TransformationMode-enum"></a>QWMatrix::TransformationMode</h3>
174
175<p> <!-- index transformation matrix -->
176<p> QWMatrix offers two transformation modes. Calculations can either
177be done in terms of points (Points mode, the default), or in
178terms of area (Area mode).
179<p> In Points mode the transformation is applied to the points that
180mark out the shape's bounding line. In Areas mode the
181transformation is applied in such a way that the area of the
182contained region is correctly transformed under the matrix.
183<ul>
184<li><tt>QWMatrix::Points</tt> - transformations are applied to the shape's points.
185<li><tt>QWMatrix::Areas</tt> - transformations are applied (e.g. to the width and
186height) so that the area is transformed.
187</ul><p> Example:
188<p> Suppose we have a rectangle,
189<tt>QRect( 10, 20, 30, 40 )</tt> and a transformation matrix
190<tt>QWMatrix( 2, 0, 0, 2, 0, 0 )</tt> to double the rectangle's size.
191<p> In Points mode, the matrix will transform the top-left (10,20) and
192the bottom-right (39,59) points producing a rectangle with its
193top-left point at (20,40) and its bottom-right point at (78,118),
194i.e. with a width of 59 and a height of 79.
195<p> In Areas mode, the matrix will transform the top-left point in
196the same way as in Points mode to (20/40), and double the width
197and height, so the bottom-right will become (69,99), i.e. a width
198of 60 and a height of 80.
199<p> Because integer arithmetic is used (for speed), rounding
200differences mean that the modes will produce slightly different
201results given the same shape and the same transformation,
202especially when scaling up. This also means that some operations
203are not commutative.
204<p> Under Points mode, <tt>matrix * ( region1 | region2 )</tt> is not equal to
205<tt>matrix * region1 | matrix * region2</tt>. Under Area mode, <tt>matrix * (pointarray[i])</tt> is not neccesarily equal to
206<tt>(matrix * pointarry)[i]</tt>.
207<p> <center><img src="xform.png" alt="Comparison of Points and Areas TransformationModes"></center>
208<hr><h2>Member Function Documentation</h2>
209<h3 class=fn><a name="QWMatrix"></a>QWMatrix::QWMatrix ()
210</h3>
211Constructs an identity matrix. All elements are set to zero except
212<em>m11</em> and <em>m22</em> (scaling), which are set to 1.
213
214<h3 class=fn><a name="QWMatrix-2"></a>QWMatrix::QWMatrix ( double&nbsp;m11, double&nbsp;m12, double&nbsp;m21, double&nbsp;m22, double&nbsp;dx, double&nbsp;dy )
215</h3>
216Constructs a matrix with the elements, <em>m11</em>, <em>m12</em>, <em>m21</em>, <em>m22</em>, <em>dx</em> and <em>dy</em>.
217
218<h3 class=fn>double <a name="det"></a>QWMatrix::det () const
219</h3>
220
221<p> Returns the matrix's determinant.
222
223<h3 class=fn>double <a name="dx"></a>QWMatrix::dx () const
224</h3>
225
226<p> Returns the horizontal translation.
227
228<h3 class=fn>double <a name="dy"></a>QWMatrix::dy () const
229</h3>
230
231<p> Returns the vertical translation.
232
233<h3 class=fn><a href="qwmatrix.html">QWMatrix</a> <a name="invert"></a>QWMatrix::invert ( bool&nbsp;*&nbsp;invertible = 0 ) const
234</h3>
235Returns the inverted matrix.
236<p> If the matrix is singular (not invertible), the identity matrix is
237returned.
238<p> If <em>invertible</em> is not 0: the value of <em>*invertible</em> is set
239to TRUE if the matrix is invertible; otherwise <em>*invertible</em> is
240set to FALSE.
241<p> <p>See also <a href="#isInvertible">isInvertible</a>().
242
243<p>Example: <a href="tutorial1-14.html#x2433">t14/cannon.cpp</a>.
244<h3 class=fn>bool <a name="isIdentity"></a>QWMatrix::isIdentity () const
245</h3>
246Returns TRUE if the matrix is the identity matrix; otherwise returns FALSE.
247<p> <p>See also <a href="#reset">reset</a>().
248
249<h3 class=fn>bool <a name="isInvertible"></a>QWMatrix::isInvertible () const
250</h3>
251
252<p> Returns TRUE if the matrix is invertible; otherwise returns FALSE.
253<p> <p>See also <a href="#invert">invert</a>().
254
255<h3 class=fn>double <a name="m11"></a>QWMatrix::m11 () const
256</h3>
257
258<p> Returns the X scaling factor.
259
260<h3 class=fn>double <a name="m12"></a>QWMatrix::m12 () const
261</h3>
262
263<p> Returns the vertical shearing factor.
264
265<h3 class=fn>double <a name="m21"></a>QWMatrix::m21 () const
266</h3>
267
268<p> Returns the horizontal shearing factor.
269
270<h3 class=fn>double <a name="m22"></a>QWMatrix::m22 () const
271</h3>
272
273<p> Returns the Y scaling factor.
274
275<h3 class=fn>void <a name="map"></a>QWMatrix::map ( int&nbsp;x, int&nbsp;y, int&nbsp;*&nbsp;tx, int&nbsp;*&nbsp;ty ) const
276</h3>
277Transforms ( <em>x</em>, <em>y</em> ) to ( <em>*tx</em>, <em>*ty</em> ) using the formulae:
278<p> <pre>
279 *tx = m11*x + m21*y + dx (rounded to the nearest integer)
280 *ty = m22*y + m12*x + dy (rounded to the nearest integer)
281 </pre>
282
283
284<p>Examples: <a href="tutorial1-14.html#x2434">t14/cannon.cpp</a> and <a href="xform-example.html#x1278">xform/xform.cpp</a>.
285<h3 class=fn>void <a name="map-2"></a>QWMatrix::map ( double&nbsp;x, double&nbsp;y, double&nbsp;*&nbsp;tx, double&nbsp;*&nbsp;ty ) const
286</h3>
287This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
288<p> Transforms ( <em>x</em>, <em>y</em> ) to ( <em>*tx</em>, <em>*ty</em> ) using the
289following formulae:
290<p> <pre>
291 *tx = m11*x + m21*y + dx
292 *ty = m22*y + m12*x + dy
293 </pre>
294
295
296<h3 class=fn><a href="qpoint.html">QPoint</a> <a name="map-3"></a>QWMatrix::map ( const&nbsp;<a href="qpoint.html">QPoint</a>&nbsp;&amp;&nbsp;p ) const
297</h3>
298
299<p> This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
300<p> Transforms <em>p</em> to using the formulae:
301<p> <pre>
302 retx = m11*px + m21*py + dx (rounded to the nearest integer)
303 rety = m22*py + m12*px + dy (rounded to the nearest integer)
304 </pre>
305
306
307<h3 class=fn><a href="qrect.html">QRect</a> <a name="map-4"></a>QWMatrix::map ( const&nbsp;<a href="qrect.html">QRect</a>&nbsp;&amp;&nbsp;r ) const
308</h3>
309
310<p> <b>This function is obsolete.</b> It is provided to keep old source working. We strongly advise against using it in new code.
311<p> Please use <a href="#mapRect">QWMatrix::mapRect</a>() instead.
312<p> Note that this method does return the bounding rectangle of the <em>r</em>, when
313shearing or rotations are used.
314
315<h3 class=fn><a href="qpointarray.html">QPointArray</a> <a name="map-5"></a>QWMatrix::map ( const&nbsp;<a href="qpointarray.html">QPointArray</a>&nbsp;&amp;&nbsp;a ) const
316</h3>
317
318<p> This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
319<p> Returns the point array <em>a</em> transformed by calling map for each point.
320
321<h3 class=fn><a href="qregion.html">QRegion</a> <a name="map-6"></a>QWMatrix::map ( const&nbsp;<a href="qregion.html">QRegion</a>&nbsp;&amp;&nbsp;r ) const
322</h3>
323
324<p> This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
325<p> Transforms the region <em>r</em>.
326<p> Calling this method can be rather expensive, if rotations or
327shearing are used.
328
329<h3 class=fn><a href="qrect.html">QRect</a> <a name="mapRect"></a>QWMatrix::mapRect ( const&nbsp;<a href="qrect.html">QRect</a>&nbsp;&amp;&nbsp;rect ) const
330</h3>
331Returns the transformed rectangle <em>rect</em>.
332<p> The bounding rectangle is returned if rotation or shearing has
333been specified.
334<p> If you need to know the exact region <em>rect</em> maps to use <a href="qsize.html#operator*-4">operator*</a>().
335<p> <p>See also <a href="qsize.html#operator*-4">operator*</a>().
336
337<p>Example: <a href="xform-example.html#x1279">xform/xform.cpp</a>.
338<h3 class=fn><a href="qpointarray.html">QPointArray</a> <a name="mapToPolygon"></a>QWMatrix::mapToPolygon ( const&nbsp;<a href="qrect.html">QRect</a>&nbsp;&amp;&nbsp;rect ) const
339</h3>
340Returns the transformed rectangle <em>rect</em> as a polygon.
341<p> Polygons and rectangles behave slightly differently
342when transformed (due to integer rounding), so
343<tt>matrix.map( QPointArray( rect ) )</tt> is not always the same as
344<tt>matrix.mapToPolygon( rect )</tt>.
345
346<h3 class=fn><a href="qregion.html">QRegion</a> <a name="mapToRegion"></a>QWMatrix::mapToRegion ( const&nbsp;<a href="qrect.html">QRect</a>&nbsp;&amp;&nbsp;rect ) const
347</h3>
348
349<p> Returns the transformed rectangle <em>rect</em>.
350<p> A rectangle which has been rotated or sheared may result in a
351non-rectangular region being returned.
352<p> Calling this method can be expensive, if rotations or shearing are
353used. If you just need to know the bounding rectangle of the
354returned region, use <a href="#mapRect">mapRect</a>() which is a lot faster than this
355function.
356<p> <p>See also <a href="#mapRect">QWMatrix::mapRect</a>().
357
358<h3 class=fn>bool <a name="operator!-eq"></a>QWMatrix::operator!= ( const&nbsp;<a href="qwmatrix.html">QWMatrix</a>&nbsp;&amp;&nbsp;m ) const
359</h3>
360Returns TRUE if this matrix is not equal to <em>m</em>; otherwise returns FALSE.
361
362<h3 class=fn><a href="qwmatrix.html">QWMatrix</a>&nbsp;&amp; <a name="operator*-eq"></a>QWMatrix::operator*= ( const&nbsp;<a href="qwmatrix.html">QWMatrix</a>&nbsp;&amp;&nbsp;m )
363</h3>
364Returns the result of multiplying this matrix by matrix <em>m</em>.
365
366<h3 class=fn>bool <a name="operator-eq-eq"></a>QWMatrix::operator== ( const&nbsp;<a href="qwmatrix.html">QWMatrix</a>&nbsp;&amp;&nbsp;m ) const
367</h3>
368Returns TRUE if this matrix is equal to <em>m</em>; otherwise returns FALSE.
369
370<h3 class=fn>void <a name="reset"></a>QWMatrix::reset ()
371</h3>
372Resets the matrix to an identity matrix.
373<p> All elements are set to zero, except <em>m11</em> and <em>m22</em> (scaling)
374which are set to 1.
375<p> <p>See also <a href="#isIdentity">isIdentity</a>().
376
377<h3 class=fn><a href="qwmatrix.html">QWMatrix</a>&nbsp;&amp; <a name="rotate"></a>QWMatrix::rotate ( double&nbsp;a )
378</h3>
379Rotates the coordinate system <em>a</em> degrees counterclockwise.
380<p> Returns a reference to the matrix.
381<p> <p>See also <a href="#translate">translate</a>(), <a href="#scale">scale</a>(), and <a href="#shear">shear</a>().
382
383<p>Examples: <a href="canvas-example.html#x2955">canvas/canvas.cpp</a>, <a href="desktop-example.html#x1764">desktop/desktop.cpp</a>, <a href="drawdemo-example.html#x1095">drawdemo/drawdemo.cpp</a>, <a href="tutorial1-14.html#x2435">t14/cannon.cpp</a>, and <a href="xform-example.html#x1280">xform/xform.cpp</a>.
384<h3 class=fn><a href="qwmatrix.html">QWMatrix</a>&nbsp;&amp; <a name="scale"></a>QWMatrix::scale ( double&nbsp;sx, double&nbsp;sy )
385</h3>
386Scales the coordinate system unit by <em>sx</em> horizontally and <em>sy</em>
387vertically.
388<p> Returns a reference to the matrix.
389<p> <p>See also <a href="#translate">translate</a>(), <a href="#shear">shear</a>(), and <a href="#rotate">rotate</a>().
390
391<p>Examples: <a href="canvas-example.html#x2956">canvas/canvas.cpp</a>, <a href="fileiconview-example.html#x876">fileiconview/qfileiconview.cpp</a>, <a href="movies-example.html#x524">movies/main.cpp</a>, <a href="qmag-example.html#x1809">qmag/qmag.cpp</a>, <a href="showimg-example.html#x1357">showimg/showimg.cpp</a>, and <a href="xform-example.html#x1281">xform/xform.cpp</a>.
392<h3 class=fn>void <a name="setMatrix"></a>QWMatrix::setMatrix ( double&nbsp;m11, double&nbsp;m12, double&nbsp;m21, double&nbsp;m22, double&nbsp;dx, double&nbsp;dy )
393</h3>
394Sets the matrix elements to the specified values, <em>m11</em>, <em>m12</em>,
395<em>m21</em>, <em>m22</em>, <em>dx</em> and <em>dy</em>.
396
397<h3 class=fn>void <a name="setTransformationMode"></a>QWMatrix::setTransformationMode ( <a href="qwmatrix.html#TransformationMode-enum">QWMatrix::TransformationMode</a>&nbsp;m )<tt> [static]</tt>
398</h3>
399Sets the transformation mode that QWMatrix and painter
400transformations use to <em>m</em>.
401<p> <p>See also <a href="#TransformationMode-enum">QWMatrix::TransformationMode</a>.
402
403<h3 class=fn><a href="qwmatrix.html">QWMatrix</a>&nbsp;&amp; <a name="shear"></a>QWMatrix::shear ( double&nbsp;sh, double&nbsp;sv )
404</h3>
405Shears the coordinate system by <em>sh</em> horizontally and <em>sv</em>
406vertically.
407<p> Returns a reference to the matrix.
408<p> <p>See also <a href="#translate">translate</a>(), <a href="#scale">scale</a>(), and <a href="#rotate">rotate</a>().
409
410<p>Examples: <a href="drawdemo-example.html#x1096">drawdemo/drawdemo.cpp</a> and <a href="xform-example.html#x1282">xform/xform.cpp</a>.
411<h3 class=fn><a href="qwmatrix.html#TransformationMode-enum">TransformationMode</a> <a name="transformationMode"></a>QWMatrix::transformationMode ()<tt> [static]</tt>
412</h3>
413Returns the current transformation mode.
414<p> <p>See also <a href="#TransformationMode-enum">QWMatrix::TransformationMode</a>.
415
416<h3 class=fn><a href="qwmatrix.html">QWMatrix</a>&nbsp;&amp; <a name="translate"></a>QWMatrix::translate ( double&nbsp;dx, double&nbsp;dy )
417</h3>
418Moves the coordinate system <em>dx</em> along the X-axis and <em>dy</em> along
419the Y-axis.
420<p> Returns a reference to the matrix.
421<p> <p>See also <a href="#scale">scale</a>(), <a href="#shear">shear</a>(), and <a href="#rotate">rotate</a>().
422
423<p>Examples: <a href="canvas-example.html#x2957">canvas/canvas.cpp</a>, <a href="drawdemo-example.html#x1097">drawdemo/drawdemo.cpp</a>, <a href="tutorial1-14.html#x2436">t14/cannon.cpp</a>, and <a href="xform-example.html#x1283">xform/xform.cpp</a>.
424<hr><h2>Related Functions</h2>
425<h3 class=fn><a href="qdatastream.html">QDataStream</a>&nbsp;&amp; <a name="operator-lt-lt"></a>operator&lt;&lt; ( <a href="qdatastream.html">QDataStream</a>&nbsp;&amp;&nbsp;s, const&nbsp;<a href="qwmatrix.html">QWMatrix</a>&nbsp;&amp;&nbsp;m )
426</h3>
427
428<p> Writes the matrix <em>m</em> to the stream <em>s</em> and returns a reference
429to the stream.
430<p> <p>See also <a href="datastreamformat.html">Format of the QDataStream operators</a>.
431
432<h3 class=fn><a href="qdatastream.html">QDataStream</a>&nbsp;&amp; <a name="operator-gt-gt"></a>operator&gt;&gt; ( <a href="qdatastream.html">QDataStream</a>&nbsp;&amp;&nbsp;s, <a href="qwmatrix.html">QWMatrix</a>&nbsp;&amp;&nbsp;m )
433</h3>
434
435<p> Reads the matrix <em>m</em> from the stream <em>s</em> and returns a reference
436to the stream.
437<p> <p>See also <a href="datastreamformat.html">Format of the QDataStream operators</a>.
438
439<!-- eof -->
440<hr><p>
441This file is part of the <a href="index.html">Qt toolkit</a>.
442Copyright &copy; 1995-2007
443<a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center>
444<table width=100% cellspacing=0 border=0><tr>
445<td>Copyright &copy; 2007
446<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
447<td align=right><div align=right>Qt 3.3.8</div>
448</table></div></address></body>
449</html>
Note: See TracBrowser for help on using the repository browser.