C++博客-misschuer

OpenResty实现限流的几种方式

此最相思 — Mon, 16 Apr 2018 08:16:00 GMT

摘要: 本文转自:http://www.itzh.org/2018/01/14/openresty_rate_limiter_methods/在开发 api 网关的时，做过一些简单的限流，比如说静态拦截和动态拦截；静态拦截说白了就是限流某一个接口在一定时间窗口的请求数。用户可以在系统上给他们的接口配置一个每秒最大调用量，如果超过这个限制，则拒绝服务此接口，而动态拦截其实也是基于静态拦截... 阅读全文

此最相思 2018-04-16 16:16 发表评论

斐波那契螺旋线

此最相思 — Mon, 11 Dec 2017 11:33:00 GMT

this.stars.push(new Star(0, 0));

        var origin:Vector2D = new Vector2D(0, 0);
        var stl = [];
        var v = new Vector2D(0, 1);
        var sp = 4;
        var rad = 2.0 * Math.PI / sp;
        for (var i = 0; i < sp; ++ i) {
            var g = rad * i;
            var ttt = v.clone();
            ttt.rotate(g);
            stl.push(ttt);
        }
        // var stl = [new Vector2D(0,1), new Vector2D(-1,0), new Vector2D(0,-1), new Vector2D(1,0)];
        var vx = [-1, 1, 1, -1];
        var vy = [-1, -1, 1, 1];
        var fib = [1, 2, 3, 5, 8, 13, 21];
        // fib = [1, 2, 3, 4, 5, 6, 7, 8];
        var temp:Vector2D = new Vector2D();
        var prev:Vector2D = new Vector2D();
        for (var i = 0; i < stl.length; ++ i) {
            // console.log("------------------");
            var s = stl[ i ];
            // console.log(s.toString());
            for (var j = 0; j < fib.length; ++ j) {
                temp.set45Vector();
                var vecx = vx[(i+j) & 3];
                var vecy = vy[(i+j) & 3];
                temp.scaleByXY(vecx * fib[ j ], vecy * fib[ j ]);

                this.stars.push(new Star(s.X, s.Y));
                s.copyTo(prev);
                s.transform(temp);
                var circleCoordinate:Vector2D = prev.cal45CircleCoordinate(s, (vecy/vecx) > 0);
                // console.log("circle coordinate", circleCoordinate.toString());

                var size = 7;
                var rad:number = Math.PI / 2 / size;
                if (j > -1) {
                    for (var k = 1; k <= size; ++ k) {
                        var tt:Vector2D = prev.clone();
                        tt.transform(circleCoordinate, false);
                        tt.rotate(rad * k);
                        tt.transform(circleCoordinate, true);
                        this.stars.push(new Star(tt.X, tt.Y));
                        // console.log("tt = ", tt.toString());
                    }
                }
                // console.log(s.toString());
            }
        }

此最相思 2017-12-11 19:33 发表评论

法线的逆转置矩阵推倒(转)

此最相思 — Wed, 06 Dec 2017 03:39:00 GMT

Transforming Planes

If we have a plane vector n = [a, b, c, d] which describes a plane then for any point p = [x, y, z, 1] in that plane the follow equation holds:

nt p = ax + by + cz + d = 0

If for a point p on the plane, we apply an invertible transformation R to get the transformed point p1, then the plane vector n1 of the transformed plane is given by applying a corresponding transformation Q to the original plane vector n where Q is unknown.

p1 = R p
n1 = Q n

We can solve for Q by using the resulting plane equation:

n1t p1 = 0

Begin by substituting for n1 and p1:

(Q n)t (R p) = 0
nt Qt R p = 0

If Qt R = I then nt Qt R p = nt I p = nt p = 0 which is given.

Qt R = I
Qt = R-1
Q = (R-1)t

Substituting Q back into our plane vector transformation equation we get:

n1 = Q n = (R-1)t n

此最相思 2017-12-06 11:39 发表评论

三维旋转(转载)

此最相思 — Mon, 04 Dec 2017 07:50:00 GMT

http://blog.csdn.net/csxiaoshui/article/details/65446125

此最相思 2017-12-04 15:50 发表评论

齐次坐标的理解(转载别人的)

此最相思 — Mon, 04 Dec 2017 06:34:00 GMT

来源 https://www.cnblogs.com/csyisong/archive/2008/12/09/1351372.html

一直对齐次坐标这个概念的理解不够彻底，只见大部分的书中说道“齐次坐标在仿射变换中非常的方便”，然后就没有了后文，今天在一个叫做“三百年重生”的博客上看到一篇关于透视投影变换的探讨的文章，其中有对齐次坐标有非常精辟的说明，特别是针对这样一句话进行了有力的证明：“齐次坐标表示是计算机图形学的重要手段之一，它既能够用来明确区分向量和点，同时也更易用于进行仿射（线性）几何变换。”—— F.S. Hill, JR。

由于作者对齐次坐标真的解释的不错，我就原封不动的摘抄过来：

对于一个向量v以及基oabc，可以找到一组坐标(v1,v2,v3)，使得v = v1 a + v2 b + v3 c （1）

而对于一个点p，则可以找到一组坐标（p1,p2,p3），使得 p – o = p1 a + p2 b + p3 c （2），

从上面对向量和点的表达，我们可以看出为了在坐标系中表示一个点（如p），我们把点的位置看作是对这个基的原点o所进行的一个位移，即一个向量——p – o（有的书中把这样的向量叫做位置向量——起始于坐标原点的特殊向量），我们在表达这个向量的同时用等价的方式表达出了点p：p = o + p1 a + p2 b + p3 c (3)

(1)(3)是坐标系下表达一个向量和点的不同表达方式。这里可以看出，虽然都是用代数分量的形式表达向量和点，但表达一个点比一个向量需要额外的信息。如果我写出一个代数分量表达(1, 4, 7)，谁知道它是个向量还是个点！

我们现在把（1）（3）写成矩阵的形式：v = (v1 v2 v3 0) X (a b c o)

p = (p1 p2 p3 1) X (a b c o),这里(a,b,c,o)是坐标基矩阵，右边的列向量分别是向量v和点p在基下的坐标。这样，向量和点在同一个基下就有了不同的表达：3D向量的第4个代数分量是0，而3D点的第4个代数分量是1。像这种这种用4个代数分量表示3D几何概念的方式是一种齐次坐标表示。

这样，上面的(1, 4, 7)如果写成（1,4,7,0），它就是个向量；如果是(1,4,7,1)，它就是个点。下面是如何在普通坐标(Ordinary Coordinate)和齐次坐标(Homogeneous Coordinate)之间进行转换：

(1)从普通坐标转换成齐次坐标时

如果(x,y,z)是个点，则变为(x,y,z,1);

如果(x,y,z)是个向量，则变为(x,y,z,0)

(2)从齐次坐标转换成普通坐标时

如果是(x,y,z,1)，则知道它是个点，变成(x,y,z);

如果是(x,y,z,0)，则知道它是个向量，仍然变成(x,y,z)

以上是通过齐次坐标来区分向量和点的方式。从中可以思考得知，对于平移T、旋转R、缩放S这3个最常见的仿射变换，平移变换只对于点才有意义，因为普通向量没有位置概念，只有大小和方向.

而旋转和缩放对于向量和点都有意义，你可以用类似上面齐次表示来检测。从中可以看出，齐次坐标用于仿射变换非常方便。

此外，对于一个普通坐标的点P=(Px, Py, Pz)，有对应的一族齐次坐标(wPx, wPy, wPz, w)，其中w不等于零。比如，P(1, 4, 7)的齐次坐标有(1, 4, 7, 1)、（2, 8, 14, 2）、（-0.1, -0.4, -0.7, -0.1）等等。因此，如果把一个点从普通坐标变成齐次坐标，给x,y,z乘上同一个非零数w，然后增加第4个分量w；如果把一个齐次坐标转换成普通坐标，把前三个坐标同时除以第4个坐标，然后去掉第4个分量。

由于齐次坐标使用了4个分量来表达3D概念，使得平移变换可以使用矩阵进行，从而如F.S. Hill, JR所说，仿射（线性）变换的进行更加方便。由于图形硬件已经普遍地支持齐次坐标与矩阵乘法，因此更加促进了齐次坐标使用，使得它似乎成为图形学中的一个标准。

以上很好的阐释了齐次坐标的作用及运用齐次坐标的好处。其实在图形学的理论中，很多已经被封装的好的API也是很有研究的，要想成为一名专业的计算机图形学的学习者，除了知其然必须还得知其所以然。这样在遇到问题的时候才能迅速定位问题的根源，从而解决问题。

此最相思 2017-12-04 14:34 发表评论

对象池(套用了网上的一个有BUG代码自己补充的没实际用过)

此最相思 — Mon, 18 May 2015 10:49:00 GMT

import java.util.Enumeration;
import java.util.Vector;

public class ObjectPool {

    private static final boolean PRINTABLE = true;
    private Class clazz = null;
    private int numObjects = 10;
    private int maxObjects = 50;
    private Vector objects = null;

    public static void main(String[] args) throws Exception {

        ObjectPool pool = new ObjectPool(XX.class);
        pool.createPool();

        XX xx = (XX) pool.getObject();
        xx.reset();
        xx.setAge(1);
        xx.setSex("M");

        pool.returnObject(xx);
        pool.closeObjectPool();
    }


    public ObjectPool(Class clazz) {

        this.clazz = clazz;
    }

    public synchronized void createPool() throws Exception {

        if (this.objects != null)
            return;

        this.objects = new Vector();
        for (int i = 0; i < this.numObjects; ++ i) {

            createObjects();
        }
    }


    public synchronized Object getObject() throws Exception {

        if (this.objects == null)
            return null;

        Object conn = this.getFreeObject();

        while (conn == null) {
            wait(250);
            conn = this.getFreeObject();
        }

        return conn;
    }


    private Object getFreeObject() throws Exception {

        Object obj = this.findFreeObject();

        if (obj == null) {

            this.createObjects();
            obj = this.findFreeObject();
            if (obj == null) {

                return null;
            }
        }

        return obj;
    }

    private void createObjects() throws Exception {

        if (this.objects.size() < this.maxObjects) {

            this.message("created" + this.objects.size());
            Object obj = this.clazz.newInstance();
            this.objects.addElement(new PooledObject(this.objects.size(), obj));
        }
    }


    private Object findFreeObject() {

        this.message("before free:--------");
        this.print();
        Object obj = null;
        PooledObject pooledObject = null;
        Enumeration enumerate = objects.elements();
        while (enumerate.hasMoreElements()) {

            pooledObject = (PooledObject) enumerate.nextElement();
            if (!pooledObject.isBusy()) {

                pooledObject.setBusy(true);
                obj = pooledObject.getObject();
                this.message("free object");
                break;
            }
        }

        this.message("after free:--------");
        this.print();

        return obj;
    }


    public void returnObject(Object obj) {

        if (this.objects == null)
            return;

        this.message("before return:--------");
        this.print();
        PooledObject pooledObject = null;
        Enumeration enumerate = objects.elements();
        while (enumerate.hasMoreElements()) {

            pooledObject = (PooledObject) enumerate.nextElement();
            if (obj == pooledObject.getObject()) {

                pooledObject.setBusy(false);
                this.message("return object");
                break;
            }
        }
        this.message("after return:--------");
        this.print();
    }


    public synchronized void closeObjectPool() {

        if (this.objects == null)
            return;

        PooledObject pooledObject = null;
        Enumeration enumerate = objects.elements();
        while (enumerate.hasMoreElements()) {

            pooledObject = (PooledObject) enumerate.nextElement();
            this.message(pooledObject.toString());
            if (pooledObject.isBusy()) {
                this.message("wait 5000");
                wait(5000);
            }
        }

        this.objects.clear();
        this.objects = null;
    }


    private void wait(int millionSeconds) {

        try {
            Thread.sleep(millionSeconds);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }


    public void print() {

        Enumeration enumerate = objects.elements();
        while (enumerate.hasMoreElements()) {

            PooledObject pooledObject = (PooledObject) enumerate.nextElement();
            this.message(pooledObject.toString());
        }

        this.message("print end==============================");
    }


    public void message(String msg) {

        if (PRINTABLE) {
            System.out.println(msg);
        }
    }


    class PooledObject {

        private int index = 0;
        Object objection = null;// 对象
        boolean busy = false; // 此对象是否正在使用的标志，默认没有正在使用

        // 构造函数，根据一个 Object 构告一个 PooledObject 对象
        public PooledObject(int index, Object objection) {

            this.index = index;
            this.objection = objection;
            this.busy = false;
        }

        // 返回此对象中的对象
        public Object getObject() {
            return objection;
        }

        // 设置此对象的，对象
        public void setObject(Object objection) {
            this.objection = objection;

        }

        // 获得对象对象是否忙
        public boolean isBusy() {
            return busy;
        }

        // 设置对象的对象正在忙
        public void setBusy(boolean busy) {
            this.busy = busy;
        }

        public int getIndex() {
            return index;
        }

        public void setIndex(int index) {
            this.index = index;
        }

        @Override
        public String toString() {

            return String.format("[PooledObject] index:%d, busy:%b", this.index, this.busy);
        }
    }
}

class XX {

    private int age = 0;
    private String sex = "";

    public XX() {

    }

    public void reset() {

        this.age = 0;
        this.sex = "";
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }
}

此最相思 2015-05-18 18:49 发表评论

centos上运行jni

此最相思 — Thu, 07 May 2015 09:14:00 GMT

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.util.StringTokenizer;

public class Test {

    public static native void hello();
        static final String LIBFILENAME = "/home/my/java/libtest.so";

    static {
        //System.loadLibrary(LIBFILENAME);

        try {
            // 获取到java.library.path  及系统变量中Path中的内容
            String libpath = System.getProperty("java.library.path");
            if (libpath == null || libpath.length() == 0) {
                throw new RuntimeException("java.library.path is null");
            }
            //javaBinPath   jdk的bin目录D:\Program Files\Java\jdk1.6.0_11\bin
            String javaBinPath = null;
            StringTokenizer st = new StringTokenizer(libpath,
                    System.getProperty("path.separator"));
            if (st.hasMoreElements()) {
                javaBinPath = st.nextToken();
            } else {
                throw new RuntimeException("can not split library path:"
                        + libpath);
            }
            // 把dll文件写入到java.library.path中该dll放在ConvertWord2HM相同目录下，这个可以是你的类名
            InputStream inputStream = Test.class.getResourceAsStream(
                    LIBFILENAME);
            final File dllFile = new File(LIBFILENAME);
            if (!dllFile.exists()) {
                FileOutputStream outputStream = new FileOutputStream(dllFile);
                byte[] array = new byte[1024];
                int bytesRead = -1;
                while ((bytesRead = inputStream.read(array)) != -1) {
                    outputStream.write(array, 0, bytesRead);
                }
                outputStream.flush();
                outputStream.close();
            }
            // 动态加载dll
            System.load(dllFile.getPath());
            // 在虚拟机关闭的时候删除dll 这里看着用吧
// dllFile.deleteOnExit();
        } catch (Throwable e) {
            throw new RuntimeException("load Convert.dll error!", e);
        }

    }
    public static void main(String[] args) {
        Test.hello();
    }
}

这个文件是在目录/home/my/java下的
javac Test.java
javah Test //生成Test.h
然后自己写Test.cpp
.java .h .cpp 这些文件名字一定要一样

g++ -I$JAVA_HOME/include -I$JAVA_HOME/include/linux -fPIC -shared -o libtest.so Test.cpp // 转成你想要的文件我这里是libtest.so 也可以是libtest.dll, 看你代码调用什么。
java Test 就可以运行了
用System.loadLibrary() 一直加载不了只能网上找了个加载lib的代码

此最相思 2015-05-07 17:14 发表评论

python3的一些包说明

此最相思 — Wed, 20 Nov 2013 03:44:00 GMT


对于ubuntu 12.04LST 安装PIL (https://github.com/sloonz/pil-py3k)

需要:
说明(http://pillow.readthedocs.org/en/latest/installation.html#linux-installation)
libjpeg8
libjpeg8-dev
libfreetype6
libfreetype6-dev
zlib1g-dev
libtiff4-dev
liblcms1-dev
libwebp-dev
tcl8.5-dev
tk8.5-dev

一定要等所有所需模块装好并且看下这个(http://jj.isgeek.net/2011/09/install-pil-with-jpeg-support-on-ubuntu-oneiric-64bits/)
然后再装PIL
再贴下网上有好心人写的生成验证码的例子

#Fly web app - Verification Code

# -*- coding: utf-8 -*-

import random

from io import BytesIO

import Image, ImageDraw, ImageFont

# 特别注意 from PIL import Image 和 import Image的区别由于PIL包都是import xxx 所以我们不能写成from xxx import yyy

class VCode:

def __init__(self,size=(100,30),length=4,font='',

font_color=(51,102,204),font_size=25,font_bg=(255,255,255),

line=(3,5),pointBorder = (50,47),save_type= 'JPEG',quality=100):

"""

验证码生成类

参数:

size - 图片高宽(width,height)

length - 验证码长度

font - 字体路径

font_color - 字体颜色(允许是: #FF0000 或 RGB)

font_size - 字体大小

font_bg - 背景颜色

line - 干扰线 (最少，最大)

pointBorder - 散点(越大越多，越大越少)

save_type - 保存类型

quality - 品质

"""

self._size = size

self._font = font

self._font_color = self._str_hex(font_color)

self._font_size = font_size

self._length = length

self._font_bg = self._str_hex(font_bg)

self._save_type = save_type

self._quality = quality

#初始化

self._im = None

self._draw = None

self._code = ''

self._char = 'abcdefghkmnprstuvwyzABCDEFGHKLMNPRSTUVWYZ23456789'

self._pointBorder = pointBorder

self._line = line

def Generate(self):

"""生成验证码，并返回图像内容，和验证码"""

#生成code

random_code = self._randomCode()

self._code = '%s' % ''.join(random_code)

code_str = '%s' % ' '.join(random_code)

#图像对象

self._im = Image.new('RGB',self._size,self._font_bg)

self._draw = ImageDraw.ImageDraw(self._im)

imFont = ImageFont.truetype(self._font,self._font_size)

w,h = imFont.getsize(self._code)

xy = ((self._size[0]-w)/2,(self._size[1]-h)/2)

self._draw.text(xy,code_str,fill=self._font_color,font=imFont)

#画干扰点

self._createPoints()

#画干扰线

self._createLines()

#file对象

fp = BytesIO()

#保存图像

self._im.save(fp,self._save_type,quality=self._quality)

return fp.getvalue(),self._code

def _str_hex(self,color):

"""转换颜色值为RGB"""

if type(color) is str:

color = color.replace('#','')

temp_color = (int(color[0:2],16),int(color[2:4],16),int(color[4:6],16))

else:

temp_color = color

return temp_color

def _randomCode(self):

"""生成随机code """

return random.sample(self._char,self._length)

def _createPoints(self):

"""画点"""

for x in range(self._size[0]):

for y in range(self._size[1]):

flag = random.randint(0, self._pointBorder[0])

if flag > self._pointBorder[1]:

self._draw.point((x, y), fill = self._randomRGB())

del flag

def _createLines(self):

"""画干扰线"""

lineNum = random.randint(self._line[0], self._line[1])

for i in range(lineNum):

begin = (random.randint(0, self._size[0]),

random.randint(0, self._size[1])

)

end = (random.randint(0, self._size[0]),

random.randint(0, self._size[1])

)

self._draw.line([begin, end], fill = self._randomRGB())

def _randomRGB(self):

"""随机生成RGB"""

return (random.randint(0,255),random.randint(0,255),random.randint(0,255))

if __name__ == "__main__":

verification = VCode(font='font/ARLRDBD.TTF')

im, code = verification.Generate()

with open("test.jpeg", "wb") as f:

f.write(im)

print(code)

用tornado render html是 html里的python 代码

Tornado的模板支持控制语句和表达语句，控制语句是使用 {% 和 %} 包起来的，例如 {% if len(items) > 2 %} 。表达语句是使用 {{ 和 }} 包起来的，例如 {{ items[0] }} 。

控制语句和对应的Python语句的格式基本完全相同。我们支持 if 、 for 、 while 和 try ，这些语句逻辑结束的位置需要用 {% end %} 做标记

图片内容无需保存到.jpeg中, 具体参考下面
http://en.wikipedia.org/wiki/Data_URI_scheme#HTML

是用mako来在html嵌套python代码
http://blog.csdn.net/luanruisong/article/details/9414635

此最相思 2013-11-20 11:44 发表评论

alchemy c 图像的缩放 (三次卷积)

此最相思 — Fri, 10 Aug 2012 02:11:00 GMT

在alchemy c中进行图片的缩放
传进的是byteArray 传出的也是byteArray 千万不要在alchemy c 中对as的对象进行函数调用那样速度很慢.... 达不到炼金术的效果...
好吧代码自己看吧还是比较简单的
alchemy c 代码
#include
#include
#include
#include <string.h>
#include
#include "AS3.h"
typedef unsigned int uint;
#define MAXV 4
using namespace std;

double SinXDivX(double x) {
    double a = -1;
    if (x < 0)
        x = -x;
    double x2 = x * x;
    double x3 = x2 * x;
    if (x <= 1)
        return (a + 2) * x3 - (a + 3) * x2 + 1;
    else if (x <= 2)
        return a * x3 - 5 * a * x2 + 8 * a * x - 4 * a;
    return 0;
}

uint availablePixel(uint *src, int srcWidth, int srcHeight, int x, int y) {
    bool flag = true;
    if (x < 0) {
        x = 0;
        flag = false;
    } else if (x >= srcWidth) {
        x = srcWidth - 1;
        flag = false;
    }
    if (y < 0) {
        y = 0;
        flag = false;
    } else if (y >= srcHeight) {
        y = srcHeight - 1;
        flag = false;
    }
    int lenth = srcWidth * srcHeight;
    int in = x + y*srcWidth;
    uint ret = src[in];
    if (!flag)
        ret = ret & 0x00ffffff;
    return ret;
}

uint border_color(double Color) {
    if (Color <= 0)
        return uint(0);
    if (Color >= 255)
        return uint(255);
    return uint(Color);
}

char *strreverse(char *a) {
    char r[10] = { 0 };
    int i, j;
    for (i = 0, j = strlen(a) - 1; a[i]; ++i, --j) {
        r[j] = a[i];
    }
    return r;
}

char *toString(uint val) {
    char a[10] = { 0 };
    char ch[16] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B',
            'C', 'D', 'E', 'F' };
    int i = 0, rt;
    if (val == 0)
        a[0] = '0';
    while (val) {
        rt = val % 16;
        val >>= 4;
        a[i++] = ch[rt];
    }
    return strreverse(a);
}

uint MatrixMutiple(double a[], uint b[][MAXV], double c[], int ii, int jj) {
    int i, j, k, z;
    double tp[MAXV], ret[MAXV], ttp[MAXV];
    memset(ret, 0.0, sizeof(ret));

    for (i = 0; i < MAXV; ++i) {
        memset(tp, 0.0, sizeof(tp));
        for (j = 0; j < MAXV; ++j) {
            tp[0] += a[j] * (b[j][i] >> 24);
            tp[1] += a[j] * ((b[j][i] & 0x00ffffff) >> 16);
            tp[2] += a[j] * ((b[j][i] & 0x0000ffff) >> 8);
            tp[3] += a[j] * (b[j][i] & 0x000000ff);
        }
        for (k = 0; k < MAXV; ++k) {
            ret[k] += c[i] * tp[k];
        }
    }

    uint af1 = border_color(ret[0] + 0.5) << 24;
    uint r1 = border_color(ret[1] + 0.5) << 16;
    uint g1 = border_color(ret[2] + 0.5) << 8;
    uint b1 = border_color(ret[3] + 0.5);

    return af1 + r1 + g1 + b1;
}

void echo(uint *val, int len) {
    int i = 0;
    for (i = 0; i < len; ++i) {
        AS3_Trace(AS3_String(toString(val[i])));
    }
}

static AS3_Val biCubic(void* self, AS3_Val args) {
    AS3_Val srcByte, dstByte;
    int srcWidth, srcHeight, dstWidth, dstHeight;
    AS3_ArrayValue(args,
            "AS3ValType, IntType, IntType, AS3ValType, IntType, IntType",
            &srcByte, &srcWidth, &srcHeight, &dstByte, &dstWidth, &dstHeight);

    int srcLen = srcWidth * srcHeight;
    int dstLen = dstWidth * dstHeight;
    uint *src = new uint[srcLen];
    uint *dst = new uint[dstLen];

    AS3_SetS(srcByte, "position", AS3_Int(0));
    AS3_ByteArray_readBytes(src, srcByte, 4 * srcLen);
    double widthFactor = 1.0 * srcWidth / dstWidth;
    double heightFactor = 1.0 * srcHeight / dstHeight;

    int i, j, k, z, gf = 0;
    double tx, ty, u, v;
    int x, y;
    double A[MAXV], C[MAXV];
    uint B[MAXV][MAXV];
    for (i = 0; i < dstWidth; ++i) {
        for (j = 0; j < dstHeight; ++j) {
            tx = (i + 0.5) * widthFactor - 0.5;
            ty = (j + 0.5) * heightFactor - 0.5;
            if (tx < 0)
                tx = -tx;
            if (ty < 0)
                ty = -ty;
            x = floor(tx);
            y = floor(ty);
            u = tx - x;
            v = ty - y;
            for (k = 0; k < MAXV; ++k) {
                A[k] = SinXDivX(u + 1.0 - k);
                C[k] = SinXDivX(v + 1.0 - k);
                for (z = 0; z < MAXV; ++z) {
                    B[k][z] = availablePixel(src, srcWidth, srcHeight,
                            x + k - 1, y + z - 1);
                }
            }
            dst[i+j*dstWidth] = MatrixMutiple(A, B, C, i, j);
        }
    }
    //echo(dst, dstLen);

    AS3_SetS(dstByte, "position", AS3_Int(0));
    AS3_ByteArray_writeBytes(dstByte, dst, 4 * dstLen);
    return AS3_True();
}

int main() {
    AS3_Val biCubicMethod = AS3_Function(NULL, biCubic);
    AS3_Val lib = AS3_Object("biCubic:AS3ValType", biCubicMethod);
    AS3_Release(biCubicMethod);
    AS3_LibInit(lib);

    return 0;
}

as 代码

package {

import cmodule.ImageScaling.CLibInit;

import flash.display.Bitmap;

import flash.display.BitmapData;

import flash.display.Sprite;

import flash.display.StageScaleMode;

import flash.geom.Rectangle;

import flash.utils.ByteArray;

import flash.utils.Timer;

[SWF(width="1000", height="600", backgroundColor="#000000", frameRate="24")]

public class Main extends Sprite {

[Embed(source='f_01.png')]

public static const image:Class;

public function Main() {

this.stage.scaleMode = StageScaleMode.NO_SCALE;

var bitmapdata:BitmapData = (new image() as Bitmap).bitmapData;

var t1:Number = (new Date()).time;

var bitmap:Bitmap = new Bitmap(Main.Cubic(bitmapdata, 256, 256));

var t2:Number = (new Date()).time;

trace((t2-t1)+"ms");

this.addChild(bitmap);

}

public static function Cubic (bitmapData:BitmapData, scalingWidth:uint, scalingHeight:uint):BitmapData {

var nbd:BitmapData = new BitmapData(scalingWidth, scalingHeight, true, 0xffffffff);

var loader:cmodule.ImageScaling.CLibInit = new cmodule.ImageScaling.CLibInit();

var lib:Object = loader.init();

var byte:ByteArray = bitmapData.getPixels(new Rectangle(0, 0, bitmapData.width, bitmapData.height));

var byte2:ByteArray = nbd.getPixels(new Rectangle(0, 0, scalingWidth, scalingHeight));

lib.biCubic(byte, bitmapData.width, bitmapData.height, byte2, scalingWidth, scalingHeight);

byte2.position = 0;

nbd.setPixels(new Rectangle(0, 0, scalingWidth, scalingHeight), byte2);

return nbd;

}

此最相思 2012-08-10 10:11 发表评论

as 图片的缩放算法 (二次线性和三次卷积)

此最相思 — Tue, 07 Aug 2012 01:58:00 GMT

package {

import flash.display.BitmapData;

public class ImageScaling {

public static var PI:Number = Math.PI;

public static function getA(val:uint):uint {

return val >>> 24;

}

public static function getR(val:uint):uint {

return (val & 0x00ffffff) >>> 16;

}

public static function getG(val:uint):uint {

return (val & 0x0000ffff) >>> 8;

}

public static function getB(val:uint):uint {

return val & 0x000000ff;

}

public static function getAA(val:Array):Array {

var ret:Array = [[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]];

for (var i:uint = 0; i < 4; ++ i) {

for (var j:uint = 0; j < 4; ++ j) {

ret[ i ][ j ] = val[ i ][ j ] >>> 24;

}

return ret;

}

public static function getRR(val:Array):Array {

var ret:Array = [[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]];

for (var i:uint = 0; i < 4; ++ i) {

for (var j:uint = 0; j < 4; ++ j) {

ret[ i ][ j ] = (val[ i ][ j ] & 0x00ffffff) >>> 16;

}

return ret;

}

public static function getGG(val:Array):Array {

var ret:Array = [[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]];

for (var i:uint = 0; i < 4; ++ i) {

for (var j:uint = 0; j < 4; ++ j) {

ret[ i ][ j ] = (val[ i ][ j ] & 0x0000ffff) >>> 8;

}

return ret;

}

public static function getBB(val:Array):Array {

var ret:Array = [[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]];

for (var i:uint = 0; i < 4; ++ i) {

for (var j:uint = 0; j < 4; ++ j) {

ret[ i ][ j ] = (val[ i ][ j ] & 0x000000ff);

}

return ret;

}

public static function availablePixel (bitmapData:BitmapData, x:uint, y:uint):uint {

var flag:Boolean = true;

if (x < 0) { x = 0; flag = false; }

else if (x >= bitmapData.width) { x = bitmapData.width - 1; flag = false; }

else if (y < 0) { y = 0; flag = false; }

else if (y >= bitmapData.height) { y = bitmapData.height - 1; flag = false; }

var ret:uint = bitmapData.getPixel32(x, y);

if (!flag) ret = ret & 0x00ffffff;

return ret;

}

public static function SinXDivX(x:Number):Number {

var a:Number = -1;

if (x < 0) x = -x;

var x2:Number = x*x;

var x3:Number = x2*x;

if (x <= 1)

return (a + 2) * x3 - (a + 3) * x2 + 1;

else if (x <= 2)

return a * x3 - 5 * a * x2 + 8 * a * x - 4 * a;

return 0;

}

public static function getPixels(a:Array, b:Array, c:Array):uint {

var arfa:Array = ImageScaling.getAA(b);

var R:Array = ImageScaling.getRR(b);

var G:Array = ImageScaling.getGG(b);

var B:Array = ImageScaling.getBB(b);

var aa:uint = ImageScaling.MatrixMutiple(a, arfa, c) << 24;

var rr:uint = ImageScaling.MatrixMutiple(a, R, c) << 16;

var gg:uint = ImageScaling.MatrixMutiple(a, G, c) << 8;

var bb:uint = ImageScaling.MatrixMutiple(a, B, c);

//trace (aa + " " + rr + " " + gg + " " + bb);

return aa + rr + gg + bb;

}

public static function border_color(Color:Number):uint {

if (Color <= 0) return uint(0);

if (Color >= 255) return uint(255);

return uint(Color);

}

public static function MatrixMutiple(a:Array, b:Array, c:Array):uint {

var ret:Number = 0;

for (var i:int = 0; i < 4; ++ i) {

var tmp:Number = 0;

for (var j:int = 0; j < 4; ++ j) {

tmp += a[ j ] * b[ j ][ i ];

}

ret += c[ i ] * tmp;

}

return border_color(ret + 0.5);

}

public static function thirdConvolution (bitmapData:BitmapData, scalingWidth:uint, scalingHeight:uint):BitmapData {

var widthFactor:Number = bitmapData.width / scalingWidth;

var heightFactor:Number = bitmapData.height / scalingHeight;

var i:uint = 0, j:uint = 0;

var nbd:BitmapData = new BitmapData(scalingWidth, scalingHeight, true, 0xffffffff);

for (i = 0; i < scalingWidth; ++ i) {

for (j = 0; j < scalingHeight; ++ j) {

var tx:Number = (i + 0.5) * widthFactor - 0.5;

var ty:Number = (j + 0.5) * heightFactor - 0.5;

if (tx < 0) tx = -tx;

if (ty < 0) ty = -ty;

var x:uint = Math.floor(tx);

var y:uint = Math.floor(ty);

var u:Number = tx - x;

var v:Number = ty - y;

var A:Array = [0.0, 0.0, 0.0, 0.0];

var B:Array = [[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]];

var C:Array = [0.0, 0.0, 0.0, 0.0];

for (var k:int = 0; k < 4; ++ k) {

A[ k ] = ImageScaling.SinXDivX(u+1.0-k);

C[ k ] = ImageScaling.SinXDivX(v+1.0-k);

for (var z:int = 0; z < 4; ++ z) {

B[ k ][ z ] = ImageScaling.availablePixel(bitmapData, x+k-1, y+z-1);

}

var p:uint = ImageScaling.getPixels(A, B, C);

nbd.setPixel32(i, j, p);

}

return nbd;

}

public static function calculator(p:Array, c:Array):uint {

return uint(p[0]*c[0]+p[1]*c[1]+p[2]*c[2]+p[3]*c[3]);

}

public static function mixedPixel(p:Array, c:Array):uint {

var aa:Array = [0, 0, 0, 0];

var ra:Array = [0, 0, 0, 0];

var ga:Array = [0, 0, 0, 0];

var ba:Array = [0, 0, 0, 0];

for (var i:uint = 0; i < 4; ++ i) {

aa[ i ] = ImageScaling.getA(p[ i ]);

ra[ i ] = ImageScaling.getR(p[ i ]);

ga[ i ] = ImageScaling.getG(p[ i ]);

ba[ i ] = ImageScaling.getB(p[ i ]);

}

return (ImageScaling.calculator(aa, c) << 24) + (ImageScaling.calculator(ra, c) << 16) + (ImageScaling.calculator(ga, c) << 8) + ImageScaling.calculator(ba, c);

}

public static function secondLinear (bitmapData:BitmapData, scalingWidth:uint, scalingHeight:uint):BitmapData {

var widthFactor:Number = bitmapData.width / scalingWidth;

var heightFactor:Number = bitmapData.height / scalingHeight;

var i:uint = 0, j:uint = 0;

var nbd:BitmapData = new BitmapData(scalingWidth, scalingHeight, true, 0xffffffff);

for (i = 0; i < scalingWidth; ++ i) {

for (j = 0; j < scalingHeight; ++ j) {

var tx:Number = i * widthFactor - 0.5;

var ty:Number = j * heightFactor - 0.5;

if (tx < 0) tx = -tx;

if (ty < 0) ty = -ty;

var x:uint = Math.floor(tx);

var y:uint = Math.floor(ty);

var u:Number = tx - x;

var v:Number = ty - y;

var ti:uint = x;

var tj:uint = y;

var p0:uint = ImageScaling.availablePixel(bitmapData, x, y);

var p1:uint = ImageScaling.availablePixel(bitmapData, x, y+1);

var p2:uint = ImageScaling.availablePixel(bitmapData, x+1, y);

var p3:uint = ImageScaling.availablePixel(bitmapData, x+1, y+1);

var pa:Array = [p0, p1, p2, p3];

var c0:Number = (1.0-u)*(1.0-v);

var c1:Number = (1.0-u)*v;

var c2:Number = u*(1.0-v);

var c3:Number = u*v;

var ca:Array = [c0, c1, c2, c3];

nbd.setPixel32(i, j, ImageScaling.mixedPixel(pa, ca));

}

return nbd;

}

测试:

package {

import flash.display.Bitmap;

import flash.display.BitmapData;

import flash.display.Sprite;

import flash.geom.Rectangle;

import flash.system.ImageDecodingPolicy;

import flash.utils.ByteArray;

[SWF(width="1000", height="600", backgroundColor="#cacaca", frameRate="24")]

public class Main extends Sprite {

[Embed(source='dog.png')]

public static const image:Class;

public function Main() {

var bitmapdata:BitmapData = (new image() as Bitmap).bitmapData

var bitmap:Bitmap = new Bitmap(showImage2(bitmapdata));

bitmap.x = 0;

bitmap.y = 0;

this.addChild(bitmap);

var bitmap2:Bitmap = new Bitmap(showImage1(bitmapdata));

bitmap2.x = 300;

bitmap2.y = 300;

this.addChild(bitmap2);

}

public static function showImage1(bitmapdata:BitmapData):BitmapData {

return ImageScaling.secondLinear(bitmapdata, 286, 300);

}

public static function showImage2(bitmapdata:BitmapData):BitmapData {

return ImageScaling.thirdConvolution(bitmapdata, 286, 300);

}

__________________________________________________
参考h ttp://blog.csdn.net/housisong/article/details/1452249

此最相思 2012-08-07 09:58 发表评论

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as 图片的缩放算法 (二次线性 和 三次卷积)

对象池(套用了网上的一个有BUG代码自己补充的没实际用过)

as 图片的缩放算法 (二次线性和三次卷积)