当画布改变宽高比时计算矩形的大小

Question

我有一个桌面应用程序，显示用户屏幕的虚拟表示。我的应用程序中画布的比例与用户屏幕的比例不匹配。

在我的应用程序中，用户可以在屏幕上添加矩形部分。添加矩形后，实际桌面上的默认大小为450x300。所以我需要调整虚拟桌面中的矩形以反映它。

所以我不能简单地这样做：

double virtualRectWidth = VirtualResolutionX / (RealResolutionX / 450);
double virtualRectHeight = virtualRectWidth / (RealResolutionX / RealResolutionY);

宽高比不匹配。

如何调整虚拟矩形的大小？

Answer 1

如果您要考虑所有可能的选项（实际高度/宽度大于/小于虚拟高度/宽度）并确保提供最佳配置（重新缩放以使可用空间最大化），它不是那么简单。以下代码说明了所有可能性：

double safeRatio = 0.95; //Avoiding identical height/width
double heightWidthRatio = virtualRectHeight / virtualRectWidth; //450 / 300
double diffWidth = safeRatio * realRectWidth - virtualRectWidth;
double diffHeight = safeRatio * realRectHeight - virtualRectHeight;
double virtualRectWidth_final = virtualRectWidth;
double virtualRectHeight_final = virtualRectHeight;

if (diffWidth <= 0 && diffHeight <= 0) //virtualRectWidth >= safeRatio*realRectWidth and virtualRectHeight >= safeRatio*realRectHeight
{
    int counterDec = 10;
    if(Math.Abs(diffWidth) > Math.Abs(diffHeight))
    {
         virtualRectWidth_final = safeRatio * realRectWidth + counterDec;
         do
         {
              virtualRectWidth_final = safeRatio * realRectWidth - counterDec;
              virtualRectHeight_final = virtualRectWidth_final * heightWidthRatio;
         } while(virtualRectHeight_final > safeRatio * realRectHeight);
    }
    else
    {
         virtualRectHeight_final = safeRatio * realRectHeight + counterDec;
         do
         {
              virtualRectHeight_final = safeRatio * realRectHeight - counterDec;
              virtualRectWidth_final = virtualRectHeight_final / heightWidthRatio;
         } while(virtualRectWidth_final > safeRatio * realRectWidth);
    }
}
else if (diffWidth <= 0) //virtualRectWidth >= safeRatio*realRectWidth
{
    virtualRectWidth_final = safeRatio * realRectWidth;
    virtualRectHeight_final = virtualRectWidth_final * heightWidthRatio;
    if (virtualRectHeight_final >= safeRatio * realRectHeight) 
    {
        virtualRectHeight_final = safeRatio * realRectHeight;
        virtualRectWidth_final = virtualRectHeight_final / heightWidthRatio;
    }
}
else if (diffHeight <= 0) //virtualRectHeight >= safeRatio*realRectHeight
{
    virtualRectHeight_final = safeRatio * realRectHeight;
    virtualRectWidth_final = virtualRectHeight_final / heightWidthRatio;
    if (virtualRectWidth_final >= safeRatio * realRectWidth)
    {
        virtualRectWidth_final = safeRatio * realRectWidth;
        virtualRectHeight_final = virtualRectWidth_final * heightWidthRatio;
    }
}
else //virtualRectWidth < safeRatio*realRectWidth && virtualRectHeight < safeRatio*realRectHeight
{
    if (diffWidth < diffHeight)
    {
        virtualRectHeight_final = virtualRectWidth_final * heightWidthRatio;
    }
    else
    {
        virtualRectWidth_final = virtualRectHeight_final / heightWidthRatio;
    }
}

最终值由virtualRectWidth_final和virtualRectHeight_final给出。通过一些工作，你可能会减少代码的大小，但重要的是结果，而且......我已经做了足够的工作来回答你的问题。