canvas draw transparent rectangle

OverviewClass android.graphics.PorterDuffXfermode inherits from android.graphics.Xfermode . When drawing with canvas in Android, you can update the final pixel color values in the canvas by blending the pixels of the drawing with porterduffxfermode

1, first say the Canvas class: class overview The Canvas class holds the "draw" calls. To draw something, your need 4 basic components:a Bitmap to hold the pixels, A Canvas to host the draw calls (writing into The bitmap), a drawing primitive (e.g.

Draw a rectangle in HTML5 Canvas, html5canvasThis article describes how to draw a rectangle in HTML5 Canvas. This article uses three APIs: fillRect, strokeRect, and clearRect. For more information, see This article is translated from Steve Fulton &

You can use the rectangle drawing function of the drawing environment to draw a rectangle fillRect to draw a solid rectangle, strokeRect to draw a hollow rectangle, and clearRect to clear the specified rectangular area to make it completely

Citation: http://blog.csdn.net/carlfan/article/details/81399841, first say the canvas class:Class OverviewThe Canvas class holds the "draw" calls. To draw something, your need 4 basic components:a Bitmap to hold the pixels, A Canvas to host the draw

Canvas is a canvas. You can use a paint brush to draw any image on it. Principle: Canvas can be regarded as a proxy or interface of the Surface. The image is drawn on the Surface. Canvas encapsulates all painting calls. Using Canvas, The content

How to Use the Shader for Canvas plotting in AndroidOverview When we use the Canvas in Android to draw various images, we can usePaint.setShader(shader)Set shader for the Paint brush, so that you can draw a colorful image. So what is the Shader?

The custom control is actually very simple. The control is actually very simple. Respect Original reprinted Please note: From AigeStudio (http://blog.csdn.net/aigestudio) Power by Aige infringement must be investigated! ArtilleryTown Building There

How does delphi use basic drawing functions to draw statistical charts? A drawing tool that comes with Windows cannot meet our drawing needs in any way. Many effects need to be implemented in other tools. How are these advanced functions

From simple basic graphics to complex, cool animations, the 2D graphics rendering context obtained through the canvas element CanvasRenderingContext2D enables graphical drawing using a rich API. This article summarizes the APIs for all the rendering