图像处理RGBA模型
R – red
G – Green
B – Blue
A – Alpha
色调、饱和度、亮度处理图像色彩
- 色调：调节物体红丶绿丶蓝具体的颜色
ColorMatrix hueMatrix = new ColorMatrix();
hueMatrix.setRotate(0, hue);//红
hueMatrix.setRotate(1, hue);//绿
hueMatrix.setRotate(2, hue);//蓝
正常值：hue = 0.0f
常用取值范围:hue ∈ (-180.0f, 180.0f)
- 饱和度：指颜色的纯度，数值0到100%（颜色从灰到饱和）进行描述。
ColorMatrix saturationMatrix = new ColorMatrix();
saturationMatrix.setSaturation(saturation);
正常值：saturation = 1.0f
常用取值范围:saturation ∈ (0.0f， 2.0f)
- 亮度：颜色的相对明暗程度
ColorMatrix lumMatrix = new ColorMatrix();
lumMatrix.setScale(lum, lum, lum, 1);
正常值：lum = 1.0f
常用取值范围:lum ∈ (0.0f, 2.0f)
- 将以上饱和度、亮度、色调融合
ColorMatrix imageMatrix = new ColorMatrix();
imageMatrix.postConcat(hueMatrix);
imageMatrix.postConcat(saturationMatrix);
imageMatrix.postConcat(lumMatrix);
- 绘制
Bitmap bmp = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bmp);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColorFilter(new ColorMatrixColorFilter(imageMatrix));
canvas.drawBitmap(bitmap, 0, 0, paint);
imageView.setImageBitmap(bmp);
原图
《将饱和调节到0》<br>hue = 0.0f<br>saturation = 0.0f<br>lum = 1.0f
《将亮度调节到2》<br>hue = 0.0f<br>saturation = 1.0f<br>lum = 2.0f
颜色矩阵变换处理图像色彩
- 上面的方式实质上也是改变的颜色矩阵来达到的效果
- 这是一个表示原图正常状态的颜色矩阵（初始化矩阵）
{1, 0, 0, 0, 0,
0, 1, 0, 0, 0,
0, 0, 1, 0, 0,
0, 0, 0, 1, 0}
- 矩阵相乘公式:颜色矩阵 x 颜色RGBA矩阵分量 = 转变后的RGBA
{a, b, c, d, e, {R {aR + bR + cR + dR + e, {R1
f, g, h, i, j, G fG + gG + hG + iG + j, G1
k, l, m, n, o, x B = kB + lB + mB + nB + o, = B1
p, q, r, s, t} A pA + qA + rA + sA + t} A1}
1}
第一行控制R
第二行控制G
第三行控制B
第四行控制A
第五列：颜色的偏移量
- 通过矩阵变换得到新的bitmap
public static Bitmap handleImageMatrix(Bitmap bitmap, float[] matrixValues) {
Bitmap bmp = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bmp);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColorFilter(new ColorMatrixColorFilter(matrixValues));
canvas.drawBitmap(bitmap, 0, 0, paint);
return bmp;
}
《原图》<br>{1, 0, 0, 0, 0,<br>0, 1, 0, 0, 0,<br>0, 0, 1, 0, 0,<br>0, 0, 0, 1, 0}
《增加100红色偏移量》<br>{1, 0, 0, 0, 100,<br>0, 1, 0, 0, 0,<br>0, 0, 1, 0, 0,<br>0, 0, 0, 1, 0}
《绿色系数改为2》<br>{1, 0, 0, 0, 0,<br>0, 2, 0, 0, 0,<br>0, 0, 1, 0, 0,<br>0, 0, 0, 1, 0}
《老照片风格》<br>{0.393, 0.769, 0.189, 0, 0,<br>0.249, 0.686, 0.168, 0, 0,<br>0.272, 0.534, 0.131, 0, 0,<br>0, 0, 0, 1, 0}
通过修改像素点处理图片色彩
- 对每个像素点进行修改，下面是一些算法
这里对每一个像素点进行处理
ABC:代表三个挨着的像素点
-
底片效果算法：
B.r = 255 - B.r;
B.g = 255 - B.g;
B.b = 255 - B.b;
-
老照片效果算法：
newR = (int) (0.393 * pixR + 0.769 * pixG + 0.189 * pixB);
newG = (int) (0.249 * pixR + 0.686 * pixG + 0.168 * pixB);
newB = (int) (0.272 * pixR + 0.534 * pixG + 0.131 * pixB);
-
浮雕效果算法：
B.r = C.r - B.r + 127;
B.g = C.g - B.g + 127;
B.b = C.b - B.b + 127;
- 下面是具体代码和效果
原图
/**
* 限制argb取值范围
*
* @param value
* @return
*/
public static int limit(int value) {
if (value > 255) {
return 255;
} else if (value < 0) {
return 0;
}
return value;
}
底片效果
/**
* 底片
*
* @param bitmap
* @return
*/
public static Bitmap handleImagePix(Bitmap bitmap) {
int width = bitmap.getWidth();
int height = bitmap.getHeight();
int r, g, b, a;
int[] imgPixels = new int[width * height];
int[] newImgPixels = new int[width * height];
bitmap.getPixels(imgPixels, 0, width, 0, 0, width, height);
for (int i = 0; i < imgPixels.length; i++) {
r = Color.red(imgPixels[i]);
g = Color.green(imgPixels[i]);
b = Color.blue(imgPixels[i]);
a = Color.alpha(imgPixels[i]);
r = limit(255 - r);
g = limit(255 - g);
b = limit(255 - b);
newImgPixels[i] = Color.argb(a, r, g, b);
}
Bitmap newBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
newBitmap.setPixels(newImgPixels, 0, width, 0, 0, width, height);
return newBitmap;
}
怀旧效果
/**
* 怀旧
*
* @param bitmap
* @return
*/
public static Bitmap handleImagePix2(Bitmap bitmap) {
int width = bitmap.getWidth();
int height = bitmap.getHeight();
int r, g, b, a, newR, newG, newB;
int[] imgPixels = new int[width * height];
int[] newImgPixels = new int[width * height];
bitmap.getPixels(imgPixels, 0, width, 0, 0, width, height);
for (int i = 0; i < imgPixels.length; i++) {
r = Color.red(imgPixels[i]);
g = Color.green(imgPixels[i]);
b = Color.blue(imgPixels[i]);
a = Color.alpha(imgPixels[i]);
newR = limit((int) (0.393 * r + 0.769 * g + 0.189 * b));
newG = limit((int) (0.249 * r + 0.686 * g + 0.168 * b));
newB = limit((int) (0.272 * r + 0.534 * g + 0.131 * b));
newImgPixels[i] = Color.argb(a, newR, newG, newB);
}
Bitmap newBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
newBitmap.setPixels(newImgPixels, 0, width, 0, 0, width, height);
return newBitmap;
}
浮雕效果
/**
* 浮雕
*
* @param bitmap
* @return
*/
public static Bitmap handleImagePix3(Bitmap bitmap) {
int width = bitmap.getWidth();
int height = bitmap.getHeight();
int r, g, b, a, cr, cg, cb;
int[] imgPixels = new int[width * height];
int[] newImgPixels = new int[width * height];
bitmap.getPixels(imgPixels, 0, width, 0, 0, width, height);
for (int i = 0; i < imgPixels.length - 1; i++) {
r = Color.red(imgPixels[i]);
g = Color.green(imgPixels[i]);
b = Color.blue(imgPixels[i]);
a = Color.alpha(imgPixels[i]);
cr = Color.red(imgPixels[i + 1]);
cg = Color.green(imgPixels[i + 1]);
cb = Color.blue(imgPixels[i + 1]);
r = limit(cr - r + 127);
g = limit(cg - g + 127);
b = limit(cb - b + 127);
newImgPixels[i] = Color.argb(a, r, g, b);
}
Bitmap newBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
newBitmap.setPixels(newImgPixels, 0, width, 0, 0, width, height);
return newBitmap;
}
图片矩阵变换实现变形效果
- 矩阵变换相乘公式
{a, b, c, X a * X + b * Y + c X′
d, e, f, x Y = d * X + e * Y + f = Y′
g, h, i} 1 g * X + h * Y + i 1′
- 初始化矩阵
{1, 0, 0,
0, 1, 0,
0, 0, 1}
- ❶平移变换
△x:表示x轴方向平移量
△y:表示y轴方向平移量
{1, 0, △x, x1 x1 + △x
0, 1, △y, x y1 = y1 + △y
0, 0, 1} 1 1
- ❷旋转变换
P点坐标(x1, y1)，连接坐标中心O，与x轴形成夹角α
r = OP
则如下等式成立
x1 = r * cosα
y1 = r * sinα
-
-
当以O为中心，r为轴，旋转θ角度，此时P点旋转后坐标为(x₂, y₂)
则如下等式成立
x2 = r * cos(α + θ) = r * cosα * cosθ - r * sinα * sinθ = x1 * cosθ - y1 * sinθ
y2 = r * sin(α + θ) = r * sinα * cosθ + r * cosα * sinθ = y1 * cosθ + x1 * sinθ
-
-
将上边等式转换成矩阵表示
{cosθ, -sinθ, 0, x1 x1 * cosθ - y1 * sinθ x2
sinθ, cosθ, 0, x y1 = y1 * cosθ + x1 * sinθ = y2
0, 0, 1} 1 1 1
- ❸缩放变换
P点坐标：(x1, y1)，x方向缩放k₁，y方向缩放k₂，
那么新P点坐标(x₂, y₂)满足以下等式：
x2 = x1 * k1
y2 = y1 * k2
-
-
将上边等式转换成矩阵表示
{k1, 0, 0, x1 x1 * k1 x2
0, k2, 0, x y1 = y1 * k2 = y2
0, 0, 1} 1 1 1
- ❹错切变换
变换公式：
x2 = x1 + y1 * k1
y2 = y1 + x1 * k2
-
-
将上边等式转换成矩阵表示
{1, k1, 0, x1 x1 + y1 * k1 x2
k2, 1, 0, x y1 = y1 + x1 * k2 = y2
0, 0, 1} 1 1 1
- 总结
{a, b, c,
d, e, f,
g, h, i}
-
-
通过上边变换得出：
a，e：控制缩放
c，f：控制平移
b，d：控制错切
效果与代码
x，y方向分别平移140像素 {1, 0, 140, 0, 1, 140, 0, 0, 1}
public class ImageMatrixView extends View{
private Bitmap bitmap;
private Matrix matrix;
public ImageMatrixView(Context context) {
super(context);
init();
}
public ImageMatrixView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public ImageMatrixView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
bitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher);
matrix = new Matrix();
float[] translateF = new float[]{
1, 0, 140,
0, 1, 140,
0, 0, 1
};
matrix.setValues(translateF);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawBitmap(ImageHelper.handleImagePix2(bitmap), 0, 0, null);
canvas.drawBitmap(bitmap, matrix, null);
}
}
{1, 1, 140, 0, 1, 140, 0, 0, 1}
{0.7f, -0.7f, 240, 0.7f, 0.7f, 0, 0, 0, 1}
安卓中提供的一些矩阵变换API接口
缩放：matrix.setScale()
旋转：matrix.setRotate()
平移：matrix.setTranslate()
错切：matrix.setSkew()
矩阵组合：matrix.post...
画笔风格实现不同图形特效
图片混合
Xfermode
图层混合结构图画布上先画上去的为Dst，后画上去的为Src。这里通过SrcIn实现图片圆角。
原图
通过设置画笔风格实现圆角
public class RoundRectView extends View {
private Bitmap outBitmap;
private Matrix matrix;
public RoundRectView(Context context) {
super(context);
init();
}
public RoundRectView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
init();
}
public RoundRectView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
setLayerType(LAYER_TYPE_SOFTWARE, null);//关闭硬件加速
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.b);
outBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(outBitmap);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
//Dst
canvas.drawRoundRect(0, 0, bitmap.getWidth(), bitmap.getHeight(), 100, 100, paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));//设置风格
//Src
canvas.drawBitmap(bitmap, 0, 0, paint);
matrix = new Matrix();//将图片缩小一倍
matrix.setScale(0.5f, 0.5f);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawBitmap(outBitmap, matrix, null);
}
}
- 与另一张图片混合
混合后的图形
public class RoundRectView extends View {
private Bitmap outBitmap;
private Matrix matrix;
public RoundRectView(Context context) {
super(context);
init();
}
public RoundRectView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
init();
}
public RoundRectView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
matrix = new Matrix();//将图片缩小
matrix.setScale(0.7f, 0.7f);
matrix.postTranslate(100f, 0f);
setLayerType(LAYER_TYPE_SOFTWARE, null);//关闭硬件加速
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.b);
Bitmap bitmap2 = BitmapFactory.decodeResource(getResources(), R.drawable.mask);
outBitmap = Bitmap.createBitmap(bitmap2.getWidth(), bitmap2.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(outBitmap);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
canvas.drawBitmap(bitmap2, matrix, null);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(bitmap, 0, 0, paint);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawBitmap(outBitmap, matrix, null);
}
}
图片渐变
Shader
线性渐变
环形渐变
扫描渐变
组合渐变
简单的实现一下倒影效果
倒影效果
public class ReflectView extends View {
private Bitmap srcBitmap;
private Bitmap refBitmap;
private Paint paint;
public ReflectView(Context context) {
super(context);
init();
}
public ReflectView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
init();
}
public ReflectView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
//1.原图片
srcBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.e);
//2.创建倒影图
Matrix matrix = new Matrix();//通过矩阵变换：y轴对折
matrix.setScale(1, -1);
refBitmap = Bitmap.createBitmap(srcBitmap, 0, 0, srcBitmap.getWidth(), srcBitmap.getHeight(), matrix, true);
//3.设置画笔渐变
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
//线性渐变
paint.setShader(new LinearGradient(0, srcBitmap.getHeight(), 0, srcBitmap.getHeight() * 1.4f,
0xDD000000, 0x10000000,
Shader.TileMode.CLAMP));
//4.设置混合模式
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawColor(Color.BLACK);
canvas.drawBitmap(srcBitmap, 0, 0, null);
canvas.drawBitmap(refBitmap, 0, srcBitmap.getHeight(), null);
canvas.drawRect(0, srcBitmap.getHeight(), srcBitmap.getWidth(), srcBitmap.getHeight() * 2, paint);
}
}
BitmapShader
- REPEAT：重复
- CLAMP：边缘拉伸
- MIRROR：镜像重复
效果
原图
REPEAT
MIRROR通过设置图像画笔画圆
原图：画笔的图像
画圆后的效果图
public class BitmapShaderView extends View {
private Bitmap bitmap;
private Paint paint;
private BitmapShader bitmapShader;
public BitmapShaderView(Context context) {
super(context);
init();
}
public BitmapShaderView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
init();
}
public BitmapShaderView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.d);
bitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
paint.setShader(bitmapShader);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawCircle(700, 400, 400, paint);
}
}
像素块处理图像drawBitmapMesh
效果图
public class MeshView extends View {
private int WIDTH = 200;//横向网格
private int HEIGHT = 200;//纵向网格
private int COUNT = (WIDTH + 1) * (HEIGHT + 1);//所有点的数量
private float[] orig = new float[COUNT * 2];//保存所有点的坐标，原始坐标
private float[] verts = new float[COUNT * 2];//保存所有点的坐标，变换后的坐标
private Bitmap bitmap;
private float k = 1;//变化偏移量
public MeshView(Context context) {
super(context);
init();
}
public MeshView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
init();
}
public MeshView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.f);
float width = bitmap.getWidth();
float height = bitmap.getHeight();
int index = 0;
//将所有点的坐标点保存到orig，verts。
//A(x1,y1)，B(x2,y2)，C(x3,y3)是挨着的三点，保存在数组中的方式为：[x1,y1,x2,y2,x3,y3]
for (int i = 0; i < HEIGHT + 1; i++) {
float fy = height * i / HEIGHT;
for (int j = 0; j < WIDTH + 1; j++) {
orig[index * 2] = verts[index * 2] = width * j / WIDTH;
orig[index * 2 + 1] = verts[index * 2 + 1] = fy + 100;
index ++;
}
}
}
@Override
protected void onDraw(Canvas canvas) {
int index = 0;
//波浪，x坐标不变，y坐标改变
for (int i = 0; i < HEIGHT + 1; i++) {
for (int j = 0; j < WIDTH + 1; j++) {
float offsetY = (float) Math.sin((float)j / WIDTH * 2 * Math.PI + k * 2 * Math.PI);
verts[index * 2 + 1] = orig[index * 2 + 1] + offsetY * 80;
index ++;
}
}
k += 0.1f;
canvas.drawBitmapMesh(bitmap, WIDTH, HEIGHT, verts, 0, null, 0, null);
invalidate();
}
}
学习路径：
Android图像处理-打造美图秀秀从它开始: http://www.imooc.com/learn/302
Android图像处理-变”换”莫测的图像: http://www.imooc.com/learn/343
