int BoxShadow_GetX( LCUI_BoxShadow *shadow )
{
if( shadow->x <= SHADOW_WIDTH(shadow) ) {
return 0;
}
return shadow->x - SHADOW_WIDTH(shadow);
}
int BoxShadow_GetBoxY( LCUI_BoxShadow *shadow )
{
if( shadow->y >= SHADOW_WIDTH(shadow) ) {
return 0;
}
return SHADOW_WIDTH(shadow) - shadow->y;
}
/** 计算Box在添加阴影后的宽度 */
int BoxShadow_GetWidth( LCUI_BoxShadow *shadow, int box_w )
{
if( shadow->x >= SHADOW_WIDTH(shadow) ) {
return box_w + SHADOW_WIDTH(shadow) + shadow->x;
}
else if( shadow->x <= -SHADOW_WIDTH(shadow) ) {
return box_w + SHADOW_WIDTH(shadow) - shadow->x;
}
return box_w + SHADOW_WIDTH(shadow)*2;
}
/** 计算Box在添加阴影后的高度 */
int BoxShadow_GetHeight( LCUI_BoxShadow *shadow, int box_h )
{
if( shadow->y >= SHADOW_WIDTH(shadow) ) {
return box_h + SHADOW_WIDTH(shadow) + shadow->y;
}
else if( shadow->y <= -SHADOW_WIDTH(shadow) ) {
return box_h + SHADOW_WIDTH(shadow) - shadow->y;
}
return box_h + SHADOW_WIDTH(shadow)*2;
}
int BoxShadow_GetBoxHeight( LCUI_BoxShadow *shadow, int h )
{
h -= SHADOW_WIDTH(shadow)*2;
if( shadow->y >= SHADOW_WIDTH(shadow) ) {
return h - shadow->y + SHADOW_WIDTH(shadow);
}
else if( shadow->y <= -SHADOW_WIDTH(shadow) ) {
return h + shadow->y + SHADOW_WIDTH(shadow);
}
return h;
}
int BoxShadow_GetBoxWidth( LCUI_BoxShadow *shadow, int w )
{
w -= SHADOW_WIDTH(shadow)*2;
/* 如果水平向右的偏移距离大于阴影宽度，说明内容区左上角与容器一致 */
if( shadow->x >= SHADOW_WIDTH(shadow) ) {
return w - (shadow->x - SHADOW_WIDTH(shadow));
}
/* 如果水平向左的偏移距离大于阴影宽度，说明阴影区左上角与容器一致 */
else if( shadow->x <= -SHADOW_WIDTH(shadow) ) {
return w + shadow->x + SHADOW_WIDTH(shadow);
}
/* 水平偏移距离没有超出阴影宽度，容器大小会是固定的，所以直接减
* 去两边的阴影宽度即可得到内容区宽度
*/
return w;
}
static void Graph_DrawRightShadow( LCUI_PaintContext paint, LCUI_Rect *box,
LCUI_BoxShadow *shadow )
{
float v, a;
int s, t, x, y, bound_x, bound_y;
LCUI_Color color;
LCUI_Graph *graph;
LCUI_Rect shadow_area, box_area, area;
box_area.x = BoxShadow_GetBoxX( shadow );
box_area.y = BoxShadow_GetBoxY( shadow );
box_area.w = BoxShadow_GetBoxWidth( shadow, box->w );
box_area.h = BoxShadow_GetBoxHeight( shadow, box->h );
shadow_area.x = BoxShadow_GetX( shadow ) + SHADOW_WIDTH(shadow);
shadow_area.x += box_area.w + INNER_SHADOW_WIDTH(shadow);
shadow_area.y = BoxShadow_GetY( shadow ) + BLUR_WIDTH(shadow);
shadow_area.w = BLUR_WIDTH(shadow);
shadow_area.h = box_area.h + INNER_SHADOW_WIDTH(shadow)*2;
color = shadow->color;
bound_x = shadow_area.x + shadow_area.w;
bound_y = shadow_area.y + shadow_area.h;
graph = Graph_GetQuote( &paint->canvas );
Graph_GetValidRect( &paint->canvas, &area );
if( !LCUIRect_GetOverlayRect( &area, &paint->rect, &area ) ) {
return;
}
s = 255;
t = BLUR_WIDTH(shadow);
v = 512.0/t;
a = 2*(v*t-s)/(t*t);
for( t=0,x=shadow_area.x; x<bound_x; ++x,++t ) {
if( x < area.x || x >= area.x + area.w ) {
continue;
}
color.alpha = (uchar_t)(s-(v*t-(a*t*t)/2));
color.alpha *= shadow->color.a/255.0;
for( y=shadow_area.y; y<bound_y; ++y ) {
if( y < area.y || y >= area.y + area.h ) {
continue;
}
if( y >= box_area.y && y < box_area.y + box_area.h
&& x >= box_area.x && x < box_area.x + box_area.w ) {
continue;
}
Graph_SetPixel( graph, x, y, color );
}
}
}
