diff --git a/.gitignore b/.gitignore
index c6cbe56..a1e84f2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,4 @@
 .DS_Store
 /build
 /captures
+/.idea
diff --git a/cslibrary/build.gradle b/cslibrary/build.gradle
index 3d70f41..6ab6b83 100644
--- a/cslibrary/build.gradle
+++ b/cslibrary/build.gradle
@@ -21,5 +21,6 @@ android {
 }
 
 dependencies {
-
+    compile 'com.android.support:support-annotations:24.2.1'
+    compile 'com.android.support:support-v4:24.2.1'
 }
diff --git a/cslibrary/src/main/java/com/hitomi/cslibrary/CrazyShadow.java b/cslibrary/src/main/java/com/hitomi/cslibrary/CrazyShadow.java
index 12234bf..b4ac643 100644
--- a/cslibrary/src/main/java/com/hitomi/cslibrary/CrazyShadow.java
+++ b/cslibrary/src/main/java/com/hitomi/cslibrary/CrazyShadow.java
@@ -102,6 +102,11 @@ public static class Builder {
          */
         private String impl;
 
+        /**
+         * Alpha to the shadow
+         */
+        private float shadowAlpha = 1.0f;
+
         /**
          * 阴影的基本色
          */
@@ -153,6 +158,15 @@ public Builder setImpl(String impl) {
             return this;
         }
 
+        /**
+         * Add alpha to the shadow.
+         * Value between 0 and 1
+         */
+        public Builder setShadowAlpha(float shadowAlpha) {
+            this.shadowAlpha = Math.max(Math.min(shadowAlpha, 1), 0);
+            return this;
+        }
+
         /**
          * 阴影的基本颜色，即最深的颜色, {@link CrazyShadowAttr#setBaseShadowColor(int)}
          * 方法会自动计算出绘制阴影时需要的 {@link #colors}
@@ -223,6 +237,7 @@ private CrazyShadow create() {
                 colors = new int[]{0x63000000, 0x32000000, 0x00000000};
             CrazyShadowAttr attr = new CrazyShadowAttr();
             attr.setImpl(impl);
+            attr.setShadowAlpha(shadowAlpha);
             attr.setBaseShadowColor(baseShadowColor);
             attr.setBackground(background);
             attr.setColors(colors);
diff --git a/cslibrary/src/main/java/com/hitomi/cslibrary/base/CrazyShadowAttr.java b/cslibrary/src/main/java/com/hitomi/cslibrary/base/CrazyShadowAttr.java
index 65ecda1..452ba30 100644
--- a/cslibrary/src/main/java/com/hitomi/cslibrary/base/CrazyShadowAttr.java
+++ b/cslibrary/src/main/java/com/hitomi/cslibrary/base/CrazyShadowAttr.java
@@ -15,6 +15,12 @@ public class CrazyShadowAttr {
      */
     private String impl;
 
+    /**
+     * Add alpha to the shadow.
+     * Value between 0 and 1
+     */
+    private float shadowAlpha = 1.0f;
+
     /**
      * 阴影的基本颜色，即最深的颜色, {@link #setBaseShadowColor(int)} 方法会自动计算出
      * 绘制阴影时需要的 {@link #colors}
@@ -50,6 +56,9 @@ public class CrazyShadowAttr {
     @CrazyShadowDirection
     private int direction;
 
+    public CrazyShadowAttr() {
+    }
+
     public String getImpl() {
         return impl;
     }
@@ -58,12 +67,17 @@ public void setImpl(String impl) {
         this.impl = impl;
     }
 
+    public void setShadowAlpha(float shadowAlpha) {
+        this.shadowAlpha = Math.max(Math.min(shadowAlpha, 1), 0);
+        this.shadowAlpha = shadowAlpha;
+    }
+
     public void setBaseShadowColor(int baseShadowColor) {
         this.baseShadowColor = baseShadowColor;
         if (colors == null) {
             colors = new int[3];
-            colors[0] = ColorUtils.setAlphaComponent(baseShadowColor, 255);
-            colors[1] = ColorUtils.setAlphaComponent(baseShadowColor, 128);
+            colors[0] = ColorUtils.setAlphaComponent(baseShadowColor, (int)(255 * shadowAlpha));
+            colors[1] = ColorUtils.setAlphaComponent(baseShadowColor, (int)(128 * shadowAlpha));
             colors[2] = ColorUtils.setAlphaComponent(baseShadowColor, 0);
         }
     }