bool GiTransform::zoomTo(const Box2d& rectWorld, const RECT_2D* rcTo, bool adjust)
{
// 如果图形范围的宽或高接近于零，就返回
if (rectWorld.isEmpty())
return false;
// 计算像素到毫米的比例
const float d2mmX = m_impl->viewScale / m_impl->w2dx;
const float d2mmY = m_impl->viewScale / m_impl->w2dy;
// 计算目标窗口区域(毫米)
float w = 0, h = 0;
Point2d ptCen;
if (rcTo != NULL) {
w = fabsf(static_cast<float>(rcTo->right - rcTo->left));
h = fabsf(static_cast<float>(rcTo->bottom - rcTo->top));
ptCen.x = (rcTo->left + rcTo->right) * 0.5f;
ptCen.y = (rcTo->top + rcTo->bottom) * 0.5f;
}
if (w < 4 || h < 4) {
w = (float)m_impl->cxWnd;
h = (float)m_impl->cyWnd;
ptCen.set(w * 0.5f, h * 0.5f);
w -= 8;
h -= 8;
}
if (w < 4 || h < 4)
return false;
w *= d2mmX;
h *= d2mmY;
ptCen.scaleBy(d2mmX, d2mmY);
// 计算新显示比例 (中心不变，缩小窗口区域使得宽高比例和图形范围相同)
float scale;
if (h * rectWorld.width() > w * rectWorld.height()) {
//h = w * rectWorld.height() / rectWorld.width();
scale = w / rectWorld.width();
}
else {
//w = h * rectWorld.width() / rectWorld.height();
scale = h / rectWorld.height();
}
// 检查显示比例
if (!adjust && ScaleOutRange(scale, m_impl))
return false;
scale = mgMax(scale, m_impl->minViewScale);
scale = mgMin(scale, m_impl->maxViewScale);
// 计算在新显示比例下显示窗口中心的世界坐标
Point2d ptW;
ptW.x = rectWorld.center().x + (m_impl->cxWnd * d2mmX * 0.5f - ptCen.x) / scale;
ptW.y = rectWorld.center().y - (m_impl->cyWnd * d2mmY * 0.5f - ptCen.y) / scale;
// 检查新显示比例下显示窗口的世界坐标范围是否在极限范围内
float halfw = m_impl->cxWnd * d2mmX / scale * 0.5f;
float halfh = m_impl->cyWnd * d2mmY / scale * 0.5f;
Box2d box (ptW, 2 * halfw, 2 * halfh);
if (!AdjustCenterIn(adjust, box, m_impl->rectLimitsW, ptW, halfw, halfh)) {
return false;
}
return m_impl->zoomNoAdjust(ptW, scale);
}
