Infinite loop because constraintlayout use int and maui use double

[xtuzy]

Problem:
i update maui example in f2d46a3, a grid split to two part, one part is a constraintlayout, but constraintlayout can't deal with it, because if grid split give a not int value, constraintlayout alway return int, that let layout will infinite loop because result have bias.

For solve this problem, i would try use px as unit when measure and layout in constraintlayout, but set property and fluentlayoytconstraintset use dp, return size to maui a dp value, that will let it not always is int.

[xtuzy]

初步在usepx分支修改后，依然无限循环。使用","时, grid传递给child的大小总是grid的大小，这导致constraintlayout也用这个大小去布局，我觉得传下来的高度应该是grid的一半，看maui的issue，造成无限循环它也可能不是我的问题，见
dotnet/maui#14694
此处是说单位转换有偏差，需要处理，
dotnet/maui#14520 此处是说新版本造成grid不对，

我需要把例子调回net6再运行下看是否是版本的问题

[xtuzy]

重新运行主分支的例子, 我看到Log中285.5 变成了285:

MeasureLayout View=ConstraintLayout Id=-1132297589 availableSize={Width=484 Height=285.5} Spec=(MeasureSpec: EXACTLY 484 x MeasureSpec: EXACTLY 285)

这是因为:

SharpConstraintLayout/SharpConstraintLayout.Maui/Widget/ConstraintLayout.cs

Line 445 in f2d46a3

int availableWidth = (int)availableSize.Width;

修改成:

int availableWidth = (int)(availableSize.Width + 0.5);
int availableHeight = (int)(availableSize.Height + 0.5);

Log中285.5 变成了286:

MeasureLayout View=ConstraintLayout Id=-1132297589 availableSize={Width=484 Height=285.5} Spec=(MeasureSpec: EXACTLY 484 x MeasureSpec: EXACTLY 286)

之后运行成功.

fix in 5afb519 , 我还增加了点对其它doube to int的修改, 暂时不知道影响, 其它测试的外观都还正常
test in a816e75 , FitGridTest的结果可以看到最终分配的大小还是按照Grid的设置分的, 所以对于ConstraintLayout来说, 内部会有1dp的偏差, 如果使用px, 偏差应该减小到1px, 但当前未打算修改

• convert dp and px