最近,当我实现模糊效果时,我正在学习RenderScript
的用法。现在我想放大部分位图。
我使用流.rs
代码来处理位图:
#pragma version(1)
#pragma rs_fp_relaxed
#pragma rs java_package_name(com.uniquestudio.renderscript)
#include "rs_debug.rsh"
int center_x,center_y;
int radius;
int scale;
int i;
int width;
uchar4 tempArray[4194304];
void init() {
i = 0;
}
uchar4 __attribute__((kernel)) traversal(uchar4 in, uint32_t x, uint32_t y) {
tempArray[i] = in;
i++;
return in;
}
uchar4 __attribute__((kernel)) invert(uchar4 in, uint32_t x, uint32_t y) {
int distance = (int) ((center_x -x) * (center_x - x) + (center_y - y) * (center_y - y));
if(distance<radius*radius){
int src_x = (int)((float)(x - center_x) / scale + center_x);
int src_y = (int)((float)(x - center_y) / scale + center_y);
return tempArray[src_y * width + src_x];
}
return in;
}
如你所见,首先我放了
像素数据到数组tempArray
。
Java代码:
public static Bitmap magnifierBitmap(Bitmap bitmap, int x, int y, int radius,int scale, Context context){
RenderScript rs = RenderScript.create(context);
Allocation in = Allocation.createFromBitmap(rs, bitmap);
Allocation out = Allocation.createTyped(rs,in.getType());
int width = bitmap.getWidth();
ScriptC_magnifier magnifier = new ScriptC_magnifier(rs);
magnifier.set_center_x(x);
magnifier.set_center_y(y);
magnifier.set_radius(radius);
magnifier.set_scale(scale);
magnifier.set_width(width);
// first call kernel method
magnifier.forEach_traversal(in,in);
// second call kernel method
magnifier.forEach_invert(in,out);
out.copyTo(bitmap);
rs.destroy();
magnifier.destroy();
in.destroy();
out.destroy();
return bitmap;
}
在java代码中,我首先调用traversal
内核方法。然后我拨打invert
。
然而它对我不起作用。
答案 0 :(得分:2)
我刚刚创建了一个示例来向您展示该过程。您可以在此处找到它:https://bitbucket.org/cmaster11/rsbookexamples/src/tip/ImageZoomExample/。
主要代码(我试图让它自动解释)如下:
// Store the input allocation
rs_allocation inputAllocation;
// Magnifying
// TODO: here, some checks should be performed to prevent atX and atY to be < 0, as well
// as them to not be greater than width and height
int atX;
int atY;
float radius;
float scale; // The scale is >= 1
// Magnifier border size, to distinguish between magnified image and original one
static float borderSize = 8.0f;
// Border color, defaults to red
static uchar4 border = {255.0f, 0.0f, 0.0f, 255.0f};
uchar4 __attribute__((kernel)) magnify(uchar4 in, int x, int y) {
// Calculates the distance between the touched point and the current kernel
// iteration pixel coordinated
// Reference: http://math.stackexchange.com/a/198769
float pointDistanceFromCircleCenter = sqrt(pow((float)(x - atX),2) + pow((float)(y - atY),2));
// Notice: NOT OPTIMIZED, is good to understand the process
float distancePow = pow(pointDistanceFromCircleCenter,2);
float radiusPow = pow(radius, 2);
// These distances show two different radiuses, which belong to the border
// of the magnifier
float borderInnerRadius = radiusPow - pow(borderSize,2);
float borderOuterRadius = radiusPow + pow(borderSize,2);
// Is this pixel outside the magnify radius?
if(distancePow > borderOuterRadius)
{
// In this case, just copy the original image
return in;
}
// Is the current pixel inside the magnifier border
else if (distancePow >= borderInnerRadius && distancePow <= borderOuterRadius)
{
// Draw border
return border;
}
// If the point is inside the magnifying inner radius, draw the magnified image
// Calculates the current distance from the chosen magnifying center
float diffX = x - atX;
float diffY = y - atY;
// Scales down the distance accordingly to scale and returns the original coordinates
int originalX = atX + round(diffX / scale);
int originalY = atY + round(diffY / scale);
// Return the original image pixel at the calculated coordinates
return rsGetElementAt_uchar4(inputAllocation, originalX, originalY);
}
// Example code
RenderScript mRS;
Allocation inputAllocation;
Allocation outputAllocation;
ScriptC_magnifier magnifier;
ImageView originalImageView;
ImageView zoomedImageView;
Bitmap inputImage, outputImage;
private void example() {
// ImageViews that will handle input and output
originalImageView = (ImageView) findViewById(R.id.imageView);
zoomedImageView = (ImageView) findViewById(R.id.imageView2);
// Initialize RenderScript context
initRS();
// Perform first magnification
magnify();
// Set up a click listener on the magnified image.
// When touched, the magnifier will be moved to the touch position.
zoomedImageView.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
int touchX = (int) event.getX();
int touchY = (int) event.getY();
Log.d("Touch", String.format("Touch: %d, %d", touchX, touchY));
magnifier.set_atX(touchX);
magnifier.set_atY(touchY);
magnify();
return false;
}
});
}
private void initRS() {
mRS = RenderScript.create(this);
// Our magnifier script
magnifier = new ScriptC_magnifier(mRS);
// Input image
inputImage = BitmapFactory.decodeResource(getResources(), R.drawable.houseimage);
originalImageView.setImageBitmap(inputImage);
inputAllocation = Allocation.createFromBitmap(mRS, inputImage);
outputAllocation = Allocation.createTyped(mRS, inputAllocation.getType());
// Initializes magnifier
magnifier.set_inputAllocation(inputAllocation);
magnifier.set_atX(300);
magnifier.set_atY(230);
magnifier.set_radius(100);
magnifier.set_scale(3);
}
private void magnify() {
// Run the kernel
magnifier.forEach_magnify(inputAllocation, outputAllocation);
// Displays the magnification output
outputImage = Bitmap.createBitmap(inputImage.getWidth(), inputImage.getHeight(), Bitmap.Config.ARGB_8888);
outputAllocation.copyTo(outputImage);
zoomedImageView.setImageBitmap(outputImage);
}
参考:RenderScript: parallel computing on Android, the easy way