【发布时间】：2025-12-18 11:30:01
【问题描述】：
我已经工作了大约 18 个小时，我变成了一个僵尸。没有你的帮助，我无法解决这个问题。
项目
我正在开发一个将 pdf 文件转换为 epub 格式的 pdf 到 epub 转换器应用程序。
问题
由于 EPub 的限制，EPub xhtml 上不允许绝对定位。因此，我决定对页面 (html) 上的所有元素（文本和图像）使用表格布局。
但我无法想象如何计算单元格的 rowspan 和 colspan 值..
我做了什么
class TableItem
{
public IRenderable Item;
public Rectangle Bounds;
public int RowSpan, ColSpan;
public TableItem(Rectangle bounds, IRenderable item)
{
this.Bounds = bounds;
this.Item = item;
}
}
class Table
{
Rectangle bounds;
List<TableItem> items;
public Table(int width, int height)
{
bounds = new Rectangle(0, 0, width, height);
items = new List<TableItem>();
}
public void Add(IRenderable item)
{
Rectangle rect = Rectangle.Intersect(bounds, item.GetBounds());
if (rect.IsEmpty)
return;
items.Add(new TableItem(rect, item));
}
List<TableItem> Slice(List<TableItem> list, int startIndex, int endIndex)
{
TableItem[] tmp = new TableItem[endIndex - startIndex];
list.CopyTo(startIndex, tmp, 0, tmp.Length);
return new List<TableItem>(tmp);
}
List<TableItem>[] Analyze(out int maxCol)
{
maxCol = 0;
if (items.Count < 1)
return new List<TableItem>[0];
/*
items.Sort
(
delegate(TableItem x, TableItem y)
{
if (x.Bounds.Y == y.Bounds.Y)
return x.Bounds.X - y.Bounds.X;
return x.Bounds.Y - y.Bounds.Y;
}
);
*/
List<Rectangle> freeAreas = new List<Rectangle>();
freeAreas.Add(bounds);
foreach (TableItem item in items)
{
for (int i = 0; i < freeAreas.Count; i++)
{
Rectangle area;
if ((area = freeAreas[i]).Contains(item.Bounds))
{
freeAreas.RemoveAt(i);
freeAreas.InsertRange(i, SplitRect(area, item.Bounds));
}
}
}
foreach (Rectangle rt in freeAreas)
items.Add(new TableItem(rt, null));
items.Sort
(
delegate(TableItem x, TableItem y)
{
if (x.Bounds.Y == y.Bounds.Y)
return x.Bounds.X - y.Bounds.X;
return x.Bounds.Y - y.Bounds.Y;
}
);
List<List<TableItem>> xlist = new List<List<TableItem>>();
int lasty = items[0].Bounds.Y;
int startIndex = 0;
for(int i=0;i<items.Count;i++)
if (lasty < items[i].Bounds.Y)
{
lasty = items[i].Bounds.Y;
List<TableItem> xl = Slice(items, startIndex, i);
xlist.Add(xl);
startIndex = i;
if (maxCol < xl.Count)
maxCol = xl.Count;
}
if (startIndex < items.Count - 1)
{
xlist.Add(Slice(items, startIndex, items.Count));
int t = xlist[xlist.Count - 1].Count;
if (maxCol < t)
t = maxCol;
}
return xlist.ToArray();
}
private Rectangle[] SplitRect(Rectangle a, Rectangle r)
{
if (a == r)
return new Rectangle[0];
if (!Rectangle.Inflate(a, -2, -2).Contains(r))
return new Rectangle[0];
#region MyRegion
if (r.X == a.X)
{
if (r.Height == a.Height)
{
#region MyRegion
return new Rectangle[]
{
new Rectangle(r.Right, a.Y, a.Width - r.Width, a.Height)
};
#endregion
}
else if (r.Y == a.Y)
{
#region MyRegion
if (r.Width == a.Width)
{
return new Rectangle[]
{
new Rectangle(a.X, r.Bottom, a.Width, a.Height - r.Height)
};
}
return new Rectangle[]
{
new Rectangle(r.Right, a.Y, a.Width - r.Width, r.Height),
new Rectangle(a.X, r.Bottom, a.Width, a.Height - r.Height)
};
#endregion
}
else if (r.Bottom == a.Bottom)
{
#region MyRegion
if (r.Width == a.Width)
{
return new Rectangle[]
{
new Rectangle(a.X, a.Y, a.Width, r.Y - a.Y)
};
}
return new Rectangle[]
{
new Rectangle(a.X, a.Y, a.Width, r.Y - a.Y),
new Rectangle(r.Right, r.Y, a.Width - r.Width, r.Height)
};
#endregion
}
else
{
#region MyRegion
if (a.Width == r.Width)
{
return new Rectangle[]
{
new Rectangle(a.X, a.Y, a.Width, a.Height - (r.Y - a.Y)),
new Rectangle(a.X, r.Bottom, a.Width, a.Height - (r.Bottom - a.Y))
};
}
return new Rectangle[]
{
new Rectangle(a.X, a.Y, a.Width, a.Height - (r.Y - a.Y)),
new Rectangle(r.Right, r.Y, a.Width - r.Right, r.Height),
new Rectangle(a.X, r.Bottom, a.Width, a.Height - (r.Bottom - a.Y))
};
#endregion
}
}
else if (r.Y == a.Y)
{
if (r.Height == a.Height)
{
#region MyRegion
if (r.Right == a.Right)
{
return new Rectangle[]
{
new Rectangle(a.X, a.Y, a.Width - r.Width, a.Height)
};
}
return new Rectangle[]
{
new Rectangle(a.X, a.Y, r.X - a.X, a.Height),
new Rectangle(r.Right, a.Y, a.Right - r.Right, a.Height)
};
#endregion
}
else
{
#region MyRegion
if (r.Right == a.Right)
{
return new Rectangle[]
{
new Rectangle(a.X, a.Y, a.Width, r.Y - a.Y),
new Rectangle(a.X, r.Y, r.X - a.X, r.Height),
new Rectangle(a.X, r.Bottom, a.Width, a.Bottom - r.Bottom)
};
}
return new Rectangle[]
{
new Rectangle(a.X, a.Y, r.X - a.X, r.Height),
Rectangle.FromLTRB(r.Right, a.Y, a.Right, r.Bottom),
Rectangle.FromLTRB(a.X, r.Bottom, a.Right, a.Bottom)
};
#endregion
}
}
else if (r.Right == a.Right)
{
#region MyRegion
if (a.Bottom == r.Bottom)
{
return new Rectangle[]
{
Rectangle.FromLTRB(a.X, a.Y, a.Right, r.Y),
Rectangle.FromLTRB(a.X, r.Y, r.X, r.Bottom)
};
}
return new Rectangle[]
{
Rectangle.FromLTRB(a.X, a.Y, a.Right, r.Y),
Rectangle.FromLTRB(a.X, r.Y, r.X, r.Bottom),
Rectangle.FromLTRB(a.X, r.Bottom, a.Right, a.Bottom)
};
#endregion
}
else if (r.Bottom == a.Bottom)
{
#region MyRegion
return new Rectangle[]
{
Rectangle.FromLTRB(a.X, a.Y, a.Right, r.Y),
Rectangle.FromLTRB(a.X, r.Y, r.X, r.Bottom),
Rectangle.FromLTRB(r.Right, r.Y, a.Right, a.Bottom)
};
#endregion
}
#endregion
return new Rectangle[]
{
Rectangle.FromLTRB(a.X, a.Y, a.Right, r.Y),
Rectangle.FromLTRB(a.X, r.Y, r.X, r.Bottom),
Rectangle.FromLTRB(r.Right, r.Y, a.Right, r.Bottom),
Rectangle.FromLTRB(a.X, r.Bottom, a.Right, a.Bottom)
};
}
public void Compose(EPubWriter writer)
{
int mc;
List<TableItem>[] all = Analyze(out mc);
if (all.Length < 1)
return;
foreach (List<TableItem> item in all)
{
writer.BeginRow();
for (int i = 0; i < item.Count; i++)
{
TableItem ti = item[i];
ti.RowSpan = 0; //???? Should Calculate
ti.ColSpan = 0; //???? Should Calculate
writer.Render(ti.Item, ti.RowSpan, ti.ColSpan);
}
writer.EndRow();
}
}
}
我需要什么
public void Compose(EPubWriter writer)
{
int mc;
// Analyze: Calculates item positions, creates
// empty TableItem s if needs, sorts by y ASC,x ASC
// Returns array of rows (TR) what contains cells (TD)
List<TableItem>[] all = Analyze(out mc);
if (all.Length < 1)
return;
foreach (List<TableItem> item in all)
{
writer.BeginRow();
for (int i = 0; i < item.Count; i++)
{
TableItem ti = item[i];
ti.RowSpan = 0; //???? Should Calculate
ti.ColSpan = 0; //???? Should Calculate
writer.Render(ti.Item, ti.RowSpan, ti.ColSpan);
}
writer.EndRow();
}
}
ti.RowSpan = 0; //???? Should Calculate ti.ColSpan = 0; //???? Should Calculate
谢谢你..
【问题讨论】：
-
天哪！ :) 在我在这里发布我的代码后，我发现我的代码上有一个错误 :))... 你能找到它吗？
-
哎呀！这个问题真的很傻吗？还是真的很难……？
标签： c# algorithm html-table