Qt的：如何让我的2D插值颜色的领域？ [英] Qt: how do I make a field of 2d-interpolated colors?

问题描述

我用C ++不少初学者，尤其是图形化有关。 我想作的动画背景，我graphicsview，看起来有点像这样的：

I'm quite a beginner with c++, especially graphically related. I would like to make an animated background for my graphicsview which looks kind of like this:

梯度场气流

再$ P $图片psents气流过一个对象的动荡。 颜色必须基于值的矩阵

The picture represents the turbulence of an airflow over an object. The colors must be based on a matrix of values.

我只能找到如何做单方向的梯度与QT。

I can only find how to do single-direction gradients with QT.

我如何设置呢？我如何获得双向梯度？

How do I set this up? How do I get two-directional gradients?

/ *编辑 它已被指出清楚，从技术上讲，这不是一个梯度，但在节点的二维数组的颜色插值。 * /

/*edit It has been pointed out well that technically speaking this is not a gradient, but an color interpolation on a 2d array of nodes. */

推荐答案

那么你没有提供的输入数据，因此没有人知道你真正想实现！

Well you have not provided the input data so no one knows what you really want to achieve !

1. 如果您有流动轨迹和大众

1. if you have the flow trajectories and mass

• ，那么你可以使用一些粒子系统+重bluring /平滑滤波达到这个
• 沿着轨迹情节抖动圆圈的颜色取决于质量/温度/速度...和色阶
任何已知点
• 在中间的固体和透明的边缘
• 渲染只是模糊/平滑图像数次后
• 这应该是它
• 少点使用的大圆圈必须很好地覆盖面积
• 也可以做多通和改变点坐标随机改善随机性的形象...

• then you can use some particle system + heavy bluring/smoothing filtering to achieve this
• for any known point along the trajectory plot a dithered circle with color depend on the mass/temp/velocity... and color scale
• solid in the middle and transparent on the edges
• after rendering just blur/smooth the image few times
• and that should be it
• less points used the bigger the circles must be to cover the area nicely
• also can do it in multi pass and change the points coordinates randomly to improve randomness in the image...

如果您有磁场强度/速度/温度或什么都网格值

if you have field strength/speed/temp or what ever grid values

• 则是类似于1
• 而不是粒子系统，你也可以做到通过四边形/平方渲染

• 二维线性渐变被称为双线性过滤

c00   -- x -->  c01

  |
  |
  y      c(x,y)
  |
  |
  V

c10              c11

C00，C01，C10，C11的角上的颜色

c00,c01,c10,c11 are corner colors

双线性插值是3倍线性插值：

Bilinear interpolation is 3x linear interpolation:

c0=c(x,0)=c00+((c01-c00)*x)
c1=c(x,1)=c10+((c11-c10)*x)
c(x,y)   =c0 +((c1 -c0 )*y)

所以呈现正方形的所有像素与上面计算的颜色，这就是你寻找

so render all pixels of the square with above computed colors and that is what you seek

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