用Unity做简易的图像处理软件（一）

2018年11月9日，星期五，晚上终于有时间玩switch了，不过在此之前，先搞一波Unity


目前，我已经添加了一些基本功能，亮度对比度饱和度，我都是用shader完成的，目前功能很少，这个shader也很简单，和屏幕后处理用的一毛一样

Shader "myshaders/BSC"
{
	Properties
	{
		_MainTex ("_MainTex", 2D) = "white" {}
		_Brightness("_Brightness",Float) = 1
		_Saturation("_Saturation",Float) = 1
		_Contrast("_Contrast",Float) = 1
	}
		SubShader
		{
			Pass
			{
				ZTest Always Cull Off ZWrite Off
				CGPROGRAM
				#pragma vertex vert
				#pragma fragment frag
				#include "UnityCG.cginc"
				sampler2D _MainTex;
				half _Brightness;
				half _Saturation;
				half _Contrast;
			struct v2a
			{
				float4 vertex : POSITION;
				float2 texcoord : TEXCOORD0;
			};

			struct v2f
			{
				float2 uv : TEXCOORD0;
				float4 pos : SV_POSITION;
			};
			v2f vert (v2a v)
			{
				v2f o;
				o.pos = UnityObjectToClipPos(v.vertex);
				o.uv = v.texcoord;
				return o;
			}
			
			fixed4 frag (v2f i) : SV_Target
			{
			fixed4 renderTex = tex2D(_MainTex,i.uv);
			fixed3 finalColor = renderTex.rgb*_Brightness;
			fixed luminance = 0.2125*renderTex.r + 0.7154*renderTex.g + 0.0721*renderTex.b;
			fixed3 luminanceColor = fixed3(luminance, luminance, luminance);
			finalColor = lerp(luminanceColor, finalColor, _Saturation);
			fixed3 avgColor = fixed3(0.5, 0.5, 0.5);//这是一个对比度为零的颜色
			finalColor = lerp(avgColor, finalColor, _Contrast);//对比度
			return fixed4(finalColor, renderTex.a);
			}
			ENDCG
		}
	}
			Fallback Off
}

这次真正的重点在于C#部分，目前已经有打开文件，更改亮度饱和度对比度，滑动滚落缩放，左键拖拽图片这几个功能
在通过OpenFileDialog得到文件路径之后，采用WWW方法拿到texture

	 WWW www = new WWW(path);
     yield return www;
     texture = www.texture;

通过Graphics.Blit把shader处理之后的texture输出到RenderTexture，再冲RT中读到texture对象中

			RenderTexture Disttexture = new RenderTexture(texture.width, texture.height, 0);
			Graphics.Blit(texture, Disttexture, material);
			int width = Disttexture.width;
            int height = Disttexture.height;
            Viewtexture = new Texture2D(width, height, TextureFormat.ARGB32, false);
            RenderTexture.active = Disttexture;
            Viewtexture.ReadPixels(new Rect(0, 0, width, height), 0, 0);
            Viewtexture.Apply();

需要特别注意的是，不要在Asset中提前创建RT，因为无法再代码中修改它的大小，还有一定要初始化代码创建的RT，万物皆对象。
完整的文件加载与图像处理C#代码如下

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using System.Windows.Forms;
public class transmit :PostEffectsBase 
{
    public Canvas uicanvas;
    public UnityEngine.UI.Image image;
    private Texture2D texture;
    public Shader processshader;
    private Material processmat;
    private Material material
    {
        get
        {
            processmat = CheckShaderAndCreateMaterial(processshader, processmat);
            return processmat;
        }
    }
    private Texture2D Viewtexture;
    private string path;
    [Range(0.0f, 3.0f)]
    public float brightness = 1.0f;
    [Range(0.0f, 3.0f)]
    public float saturation = 1.0f;
    [Range(0.0f, 3.0f)]
    public float contrast = 1.0f;
    public Slider slider1;
    public void BscChange1()
    {
        brightness = slider1.value;
        Updateimage();
    }
    public Slider slider2;
    public void BscChange2()
    {
        saturation = slider2.value;
        Updateimage();
    }
    public Slider slider3;
    public void BscChange3()
    {
        contrast = slider3.value;
        Updateimage();
    }
    public UnityEngine.UI.Button selectfile;
    public void Selectpic()
    {
        OpenFileDialog dialog = new OpenFileDialog();
        dialog.Multiselect = false;//只能选择一个文件
        dialog.Title = "请选择图片";
        dialog.Filter = "图像文件(*bmp;*.jpg;*.jpeg;*.png)|*bmp;*.jpg;*.jpeg;*.png";
        if (dialog.ShowDialog() == DialogResult.OK)
        {
            path = dialog.FileName;
            selectfile.gameObject.SetActive(false);
            image.color = new Color32(255, 255, 255, 255);
            StartCoroutine(Load());
        }
    }
    IEnumerator Load()
    {
        WWW www = new WWW(path);
        yield return www;
        texture = www.texture;
        image.GetComponent<RectTransform>().sizeDelta = new Vector2(texture.width, texture.height);
        Sprite sprite = Sprite.Create(texture, new Rect(0, 0, texture.width, texture.height), new Vector2(0.5f, 0.5f));
        image.sprite = sprite;
        Gamevars.textureisable = true;
        Gamevars.imagewidth = texture.width;
        Gamevars.imageheight = texture.height;

    }
    //private RenderTexture Rt;
    private void Updateimage()
    {
        if (Gamevars.textureisable)
        {
            material.SetFloat("_Brightness", brightness);
            material.SetFloat("_Saturation", saturation);
            material.SetFloat("_Contrast", contrast);
            RenderTexture Disttexture = new RenderTexture(texture.width, texture.height, 0);
            Graphics.Blit(texture, Disttexture, material);
            //Debug.Log(Disttexture == null);
            int width = Disttexture.width;
            int height = Disttexture.height;
            Viewtexture = new Texture2D(width, height, TextureFormat.ARGB32, false);
            RenderTexture.active = Disttexture;
            Viewtexture.ReadPixels(new Rect(0, 0, width, height), 0, 0);
            Viewtexture.Apply();
            image.GetComponent<RectTransform>().sizeDelta = new Vector2(Viewtexture.width, Viewtexture.height);
            Sprite sprite = Sprite.Create(Viewtexture, new Rect(0, 0, Viewtexture.width, Viewtexture.height), new Vector2(0.5f, 0.5f));//因为居中显示所以.5f
            image.sprite = sprite;
            Refresh();
        }
    }
    private void Refresh()
    {
        image.GetComponent<RectTransform>().sizeDelta = new Vector2(Gamevars.imagewidth, Gamevars.imageheight) * Gamevars.size;
    }
}

之后便是图片缩放，拖拽代码，这两个功能并没有对图片本身加工，而是为了方便用户操作

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
public struct Gamevars
{//方便两个脚本之间传递，控制整个程序
    public static bool textureisable=false;//当前打开了图片
    public static int imagewidth = 0;
    public static int imageheight = 0;
    public static float size=1;
    public static Vector2 offect=new Vector2(0,0);
}
public class gamectrl : MonoBehaviour {
    private float xx = 0;
    private float yy = 0;
    public Text size1;
    public Camera ca;
    public Image image;
    [Range(.1f, 1f)]
    public float smooth=.1f;
    private Vector2 vectormtoo;
    private float fire = 0;
    // Use this for initialization
    void Start () {
	}
	
	// Update is called once per frame
	void Update () {
        
        if (Gamevars.textureisable)
        {

            if (Input.GetAxis("Mouse ScrollWheel") != 0)
            {//这个缩放真的搞得我。。。
                Vector2 mid = new Vector2(Gamevars.imagewidth, Gamevars.imageheight) * Gamevars.size;
                Gamevars.size += Input.GetAxis("Mouse ScrollWheel") * smooth;
                Vector2 sizedelta= new Vector2(Gamevars.imagewidth, Gamevars.imageheight) * Gamevars.size;
                mid = sizedelta - mid;//用来记录缩放量
                Vector2 originpos = new Vector2(image.transform.position.x, image.transform.position.y - sizedelta.y);
                Vector2 mousepos = Input.mousePosition;
                Vector2 mouseposinimage = mousepos - originpos;
                xx = mouseposinimage.x / sizedelta.x;
                yy = mouseposinimage.y / sizedelta.y;
                image.GetComponent<RectTransform>().sizeDelta = sizedelta;
                size1.text = ((int)(Gamevars.size * 100)).ToString() + "%";
                if (!(xx < 0 || xx > 1 || yy < 0 ||yy > 1))
                {
                    //Debug.Log(xx);
                    //Debug.Log(yy);
                   image.GetComponent<RectTransform>().Translate(new Vector3(-xx * mid.x, (1-yy)* mid.y, 0));//因为锚点在左上角
                }
            }
            if (Input.GetAxis("Fire1") != 0&&Input.mousePosition.x<=900)
            {
                
                Vector2 mousepos = Input.mousePosition;
                if (fire == 0) {
                    vectormtoo = mousepos - (Vector2)image.transform.position;
                    fire = 1;
                }
                image.transform.position = mousepos - vectormtoo;
            }
            if (fire==1&&Input.GetAxis("Fire1") == 0)
            {
                fire = 0;
            }
        }

	}
}

缩放的主要思路是：获取图片左下角的坐标originpos，通过这个坐标获取鼠标在图片上的坐标mouseposinimage，然后，计算放大缩小的的增减，来位移image（因为我需要的是以鼠标为原点进行缩放，至少看起来只这样）
需要注意的是这里

                xx = mouseposinimage.x / sizedelta.x;
                yy = mouseposinimage.y / sizedelta.y;

我为什么不直接

	Vector2 xy=mouseposinimage/sizedelta;

这个多方便，然而，这个xx，yy是我用来检查鼠标在图片上的位置的，如果直接用Vector2/Vector2，它的精度会降低到0.1，而xx，yy是一个[0,1]的值，这个精度实在满足不了我，如果有大佬路过这里，希望可以顺手指点我一下。
正如各位大佬所见，这个软件还是一个半成品 ，啊不，0.1成品，后续我会添加很多功能，都是通过RT来完成，后续的文章可能要偏向shader一点了。