1 /****************************************************************************

     2 ** 

     3 **

     4 ** Copyright (C) 1992-1998 Troll Tech AS.  All rights reserved.

     5 **

     6 ** This file is part of an example program for Qt.  This example

     7 ** program may be used, distributed and modified without limitation.

     8 **

     9 *****************************************************************************/

    10 

    11 #include "hello.h"

    12 #include <qpushbutton.h>

    13 #include <qtimer.h>

    14 #include <qpainter.h>

    15 #include <qpixmap.h>

    16 

    17 

    18 /*

    19   Constructs a Hello widget. Starts a 40 ms animation timer.

    20 */

    21 

    22 Hello::Hello( const char *text, QWidget *parent, const char *name )

    23     : QWidget(parent,name), t(text), b(0)

    24 {

    25     QTimer *timer = new QTimer(this);

    26     connect( timer, SIGNAL(timeout()), SLOT(animate()) );

    27     timer->start( 40 );

    28 

    29     resize( 200, 100 );

    30 }

    31 

    32 

    33 /*

    34   This private slot is called each time the timer fires.

    35 */

    36 

    37 void Hello::animate()

    38 {

    39     b = (b + 1) & 15;

    40     repaint( FALSE );

    41 }

    42 

    43 

    44 /*

    45   Handles mouse button release events for the Hello widget.

    46 

    47   We emit the clicked() signal when the mouse is released inside

    48   the widget.

    49 */

    50 

    51 void Hello::mouseReleaseEvent( QMouseEvent *e )

    52 {

    53     if ( rect().contains( e->pos() ) )

    54 	emit clicked();

    55 }

    56 

    57 

    58 /*

    59   Handles paint events for the Hello widget.

    60 

    61   Flicker-free update. The text is first drawn in the pixmap and the

    62   pixmap is then blt'ed to the screen.

    63 */

    64 

    65 void Hello::paintEvent( QPaintEvent * )

    66 {

    67     static int sin_tbl[16] = {

    68 	0, 38, 71, 92, 100, 92, 71, 38,	0, -38, -71, -92, -100, -92, -71, -38};

    69 

    70     if ( t.isEmpty() )

    71 	return;

    72 

    73     // 1: Compute some sizes, positions etc.

    74     QFontMetrics fm = fontMetrics();

    75     int w = fm.width(t) + 20;

    76     int h = fm.height() * 2;

    77     int pmx = width()/2 - w/2;

    78     int pmy = height()/2 - h/2;

    79 

    80     // 2: Create the pixmap and fill it with the widget's background

    81     QPixmap pm( w, h );

    82     pm.fill( this, pmx, pmy );

    83 

    84     // 3: Paint the pixmap. Cool wave effect

    85     QPainter p;

    86     int x = 10;

    87     int y = h/2 + fm.descent();

    88     int i = 0;

    89     p.begin( &pm );

    90     p.setFont( font() );

    91     while ( t[i] ) {

    92 	int i16 = (b+i) & 15;

    93         p.setPen( QColor((15-i16)*16,255,255,QColor::Hsv) );

    94 	p.drawText( x, y-sin_tbl[i16]*h/800, &t[i], 1 );

    95 	x += fm.width( t[i] );

    96 	i++;

    97     }

    98     p.end();

    99 

   100     // 4: Copy the pixmap to the Hello widget

   101     bitBlt( this, pmx, pmy, &pm );

   102 }