版本为2.3.10
在ScrollBar的设计中利用drawArrow画箭头，但是觉得箭头太小，想采用大点的，找到该函数是以下的描述，由于时间不够，发上来谁弄过的帮忙看下，谢谢
QMotifStyle::drawArrow( QPainter *p, ArrowType type, bool down,
int x, int y, int w, int h,
const QColorGroup &g, bool enabled, const QBrush * /* fill */ )
{
// ### may be worth caching these as pixmaps, especially with the
// cost of rotate() for vertical arrows.
QPointArray bFill; // fill polygon
QPointArray bTop; // top shadow.
QPointArray bBot; // bottom shadow.
QPointArray bLeft; // left shadow.
QWMatrix matrix; // xform matrix
bool vertical = type == UpArrow || type == DownArrow;
bool horizontal = !vertical;
int dim = w < h ? w : h;
int colspec = 0x0000; // color specification array
if ( dim < 2 ) // too small arrow
return;
// adjust size and center (to fix rotation below)
if ( w > dim ) {
x += (w-dim)/2;
w = dim;
}
if ( h > dim ) {
y += (h-dim)/2;
h = dim;
}
if ( dim > 3 ) {
if ( dim > 6 )
bFill.resize( dim & 1 ? 3 : 4 );
bTop.resize( (dim/2)*2 );
bBot.resize( dim & 1 ? dim + 1 : dim );
bLeft.resize( dim > 4 ? 4 : 2 );
bLeft.putPoints( 0, 2, 0,0, 0,dim-1 );
if ( dim > 4 )
bLeft.putPoints( 2, 2, 1,2, 1,dim-3 );
bTop.putPoints( 0, 4, 1,0, 1,1, 2,1, 3,1 );
bBot.putPoints( 0, 4, 1,dim-1, 1,dim-2, 2,dim-2, 3,dim-2 );
for( int i=0; i<dim/2-2 ; i++ ) {
bTop.putPoints( i*2+4, 2, 2+i*2,2+i, 5+i*2, 2+i );
bBot.putPoints( i*2+4, 2, 2+i*2,dim-3-i, 5+i*2,dim-3-i );
}
if ( dim & 1 ) // odd number size: extra line
bBot.putPoints( dim-1, 2, dim-3,dim/2, dim-1,dim/2 );
if ( dim > 6 ) { // dim>6: must fill interior
bFill.putPoints( 0, 2, 1,dim-3, 1,2 );
if ( dim & 1 ) // if size is an odd number
bFill.setPoint( 2, dim - 3, dim / 2 );
else
bFill.putPoints( 2, 2, dim-4,dim/2-1, dim-4,dim/2 );
}
}
else {
if ( dim == 3 ) { // 3x3 arrow pattern
bLeft.setPoints( 4, 0,0, 0,2, 1,1, 1,1 );
bTop .setPoints( 2, 1,0, 1,0 );
bBot .setPoints( 2, 1,2, 2,1 );
}
else { // 2x2 arrow pattern
bLeft.setPoints( 2, 0,0, 0,1 );
bTop .setPoints( 2, 1,0, 1,0 );
bBot .setPoints( 2, 1,1, 1,1 );
}
}
if ( type == UpArrow || type == LeftArrow ) {
matrix.translate( x, y );
if ( vertical ) {
matrix.translate( 0, h - 1 );
matrix.rotate( -90 );
} else {
matrix.translate( w - 1, h - 1 );
matrix.rotate( 180 );
}
if ( down )
colspec = horizontal ? 0x2334 : 0x2343;
else
colspec = horizontal ? 0x1443 : 0x1434;
}
else if ( type == DownArrow || type == RightArrow ) {
matrix.translate( x, y );
if ( vertical ) {
matrix.translate( w-1, 0 );
matrix.rotate( 90 );
}
if ( down )
colspec = horizontal ? 0x2443 : 0x2434;
else
colspec = horizontal ? 0x1334 : 0x1343;
}
QColor *cols[5];
if ( enabled ) {
cols[0] = 0;
cols[1] = (QColor *)&g.button();
cols[2] = (QColor *)&g.mid();
cols[3] = (QColor *)&g.light();
cols[4] = (QColor *)&g.dark();
} else {
cols[0] = 0;
cols[1] = (QColor *)&g.button();
cols[2] = (QColor *)&g.button();
cols[3] = (QColor *)&g.button();
cols[4] = (QColor *)&g.button();
}
#define CMID *cols[ (colspec>>12) & 0xf ]
#define CLEFT *cols[ (colspec>>8) & 0xf ]
#define CTOP *cols[ (colspec>>4) & 0xf ]
#define CBOT *cols[ colspec & 0xf ]
QPen savePen = p->pen(); // save current pen
QBrush saveBrush = p->brush(); // save current brush
QWMatrix wxm = p->worldMatrix();
QPen pen( NoPen );
QBrush brush = g.brush( enabled?QColorGroup::Button:QColorGroup::Mid );
p->setPen( pen );
p->setBrush( brush );
p->setWorldMatrix( matrix, TRUE ); // set transformation matrix
p->drawPolygon( bFill ); // fill arrow
p->setBrush( NoBrush ); // don't fill
p->setPen( CLEFT );
p->drawLineSegments( bLeft );
p->setPen( CTOP );
p->drawLineSegments( bTop );
p->setPen( CBOT );
p->drawLineSegments( bBot );
p->setWorldMatrix( wxm );
p->setBrush( saveBrush ); // restore brush
p->setPen( savePen ); // restore pen
#undef CMID
#undef CLEFT
#undef CTOP
#undef CBOT
}
