热图 - 生成简单“HeatPoint”谷歌地图Android版 [英] Heatmap - Generating Simple 'HeatPoint' Google Maps Android

问题描述

Android SDK中2.3.3
谷歌地图V2

Android SDK 2.3.3 Google Maps V2

目前我画界重叠并将它们添加到一个图形页面。大小由一定的价值决定的，我期待用别的东西来决定圆的颜色的RadialGradient

Currently I'm drawing circles overlays and adding them to a MapView. The size is dictated by a certain value and I'm looking to determine the RadialGradient color of the circle by something else.

            circle.setShader(new RadialGradient(pt.x, pt.y, 40, Color.argb(150, 252, 5, 5), Color.argb(60, 234, 231, 0), TileMode.MIRROR));
            canvas.drawCircle(pt.x, pt.y, radius, circle);

它的工作原理，但我想preFER边缘看起来更类似于经典的heatpoint地图。

It works, however I'd prefer the edges to look more similar to the classic heatpoint map.

目前

想我实现（我还是很喜欢的形状是圆形的）

What I'd like to achieve (I'd still like the shape to be circular)

我在想可能是为了实现一个更典型的热图直视画圆目前下方有悦目面积较大，然而，这会对性能产生影响考虑，我有重新在移动设备上这样做每变焦​​-render或失去作用。

I'm thinking of possibly drawing a circle directly underneath the current with a sightly bigger area in order to achieve a more typical heatmap look, however this has performance implications considering I'm doing this on a mobile device which has to re-render per zoom in or out action.

推荐答案

有几个明显的选择这里，我敢肯定还有更多的非明显的方式做到这一点还有：

There are a few obvious options here, and I'm sure there are many more non-obvious ways to do this as well:

• 绘制多个同心圆如你所说


• 加载从图像同心圆图案绘制（不渲染，但是，当然，你必须加载图片）


• 使用一个 BitmapShader 来绘制一个自定义渐变单圈匹配您要查找的内容：的 http://developer.android.com/reference/android/graphics/BitmapShader.html

• Draw multiple concentric circles as you suggested
• Load a concentric circle pattern from an image and draw that (less rendering, but, of course, you have to load the image)
• Use a BitmapShader to draw a single circle with a custom gradient that matches what you're looking for: http://developer.android.com/reference/android/graphics/BitmapShader.html

不幸的是，我不知道这些选项中会给你最好的性能，所以你可能必须自己进行测试。我怀疑，对于大量的热图点，后来的两个选项之一将更有效率，但是这只不过是一个猜测。

Unfortunately, I don't know which of these options will give you the best performance, so you'll probably have to test them yourself. I suspect that, for a large number of heatmap points, one of the later two options will be more efficient, but that's nothing more than a guess.

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