diff --git a/backend/gogl/gogl.go b/backend/gogl/gogl.go
index ba45027..0d39d8c 100644
--- a/backend/gogl/gogl.go
+++ b/backend/gogl/gogl.go
@@ -312,8 +312,6 @@ func (b *GoGLBackend) useShader(style *backendbase.FillStyle) (vertexLoc uint32)
 		length := dir.len()
 		dir = dir.scale(1 / length)
 		gl.Uniform2f(b.lgr.CanvasSize, float32(b.fw), float32(b.fh))
-		inv := mat(style.FillMatrix).invert().f32()
-		gl.UniformMatrix3fv(b.lgr.Invmat, 1, false, &inv[0])
 		gl.Uniform2f(b.lgr.From, float32(from[0]), float32(from[1]))
 		gl.Uniform2f(b.lgr.Dir, float32(dir[0]), float32(dir[1]))
 		gl.Uniform1f(b.lgr.Len, float32(length))
@@ -329,8 +327,6 @@ func (b *GoGLBackend) useShader(style *backendbase.FillStyle) (vertexLoc uint32)
 		from := mat(style.FillMatrix).mul(rg.from)
 		to := mat(style.FillMatrix).mul(rg.to)
 		gl.Uniform2f(b.rgr.CanvasSize, float32(b.fw), float32(b.fh))
-		inv := mat(style.FillMatrix).invert().f32()
-		gl.UniformMatrix3fv(b.rgr.Invmat, 1, false, &inv[0])
 		gl.Uniform2f(b.rgr.From, float32(from[0]), float32(from[1]))
 		gl.Uniform2f(b.rgr.To, float32(to[0]), float32(to[1]))
 		gl.Uniform1f(b.rgr.RadFrom, float32(rg.radFrom))
@@ -345,8 +341,6 @@ func (b *GoGLBackend) useShader(style *backendbase.FillStyle) (vertexLoc uint32)
 		gl.ActiveTexture(gl.TEXTURE0)
 		gl.BindTexture(gl.TEXTURE_2D, img.tex)
 		gl.Uniform2f(b.ipr.CanvasSize, float32(b.fw), float32(b.fh))
-		inv := mat(style.FillMatrix).invert().f32()
-		gl.UniformMatrix3fv(b.ipr.Invmat, 1, false, &inv[0])
 		gl.Uniform2f(b.ipr.ImageSize, float32(img.w), float32(img.h))
 		gl.Uniform1i(b.ipr.Image, 0)
 		gl.Uniform1f(b.ipr.GlobalAlpha, float32(style.Color.A)/255)
@@ -373,8 +367,6 @@ func (b *GoGLBackend) useAlphaShader(style *backendbase.FillStyle, alphaTexSlot
 		length := dir.len()
 		dir = dir.scale(1 / length)
 		gl.Uniform2f(b.lgar.CanvasSize, float32(b.fw), float32(b.fh))
-		inv := mat(style.FillMatrix).invert().f32()
-		gl.UniformMatrix3fv(b.lgar.Invmat, 1, false, &inv[0])
 		gl.Uniform2f(b.lgar.From, float32(from[0]), float32(from[1]))
 		gl.Uniform2f(b.lgar.Dir, float32(dir[0]), float32(dir[1]))
 		gl.Uniform1f(b.lgar.Len, float32(length))
@@ -391,8 +383,6 @@ func (b *GoGLBackend) useAlphaShader(style *backendbase.FillStyle, alphaTexSlot
 		from := mat(style.FillMatrix).mul(rg.from)
 		to := mat(style.FillMatrix).mul(rg.to)
 		gl.Uniform2f(b.rgar.CanvasSize, float32(b.fw), float32(b.fh))
-		inv := mat(style.FillMatrix).invert().f32()
-		gl.UniformMatrix3fv(b.rgar.Invmat, 1, false, &inv[0])
 		gl.Uniform2f(b.rgar.From, float32(from[0]), float32(from[1]))
 		gl.Uniform2f(b.rgar.To, float32(to[0]), float32(to[1]))
 		gl.Uniform1f(b.rgar.RadFrom, float32(rg.radFrom))
@@ -408,8 +398,6 @@ func (b *GoGLBackend) useAlphaShader(style *backendbase.FillStyle, alphaTexSlot
 		gl.ActiveTexture(gl.TEXTURE0)
 		gl.BindTexture(gl.TEXTURE_2D, img.tex)
 		gl.Uniform2f(b.ipar.CanvasSize, float32(b.fw), float32(b.fh))
-		inv := mat(style.FillMatrix).invert().f32()
-		gl.UniformMatrix3fv(b.ipar.Invmat, 1, false, &inv[0])
 		gl.Uniform2f(b.ipar.ImageSize, float32(img.w), float32(img.h))
 		gl.Uniform1i(b.ipar.Image, 0)
 		gl.Uniform1i(b.ipar.AlphaTex, alphaTexSlot)
diff --git a/backend/gogl/shaders.go b/backend/gogl/shaders.go
index c42057e..c9c6605 100755
--- a/backend/gogl/shaders.go
+++ b/backend/gogl/shaders.go
@@ -61,14 +61,12 @@ var linearGradientFS = `
 precision mediump float;
 #endif
 varying vec2 v_cp;
-uniform mat3 invmat;
 uniform sampler2D gradient;
 uniform vec2 from, dir;
 uniform float len;
 uniform float globalAlpha;
 void main() {
-	vec3 untf = vec3(v_cp, 1.0) * invmat;
-	vec2 v = untf.xy - from;
+	vec2 v = v_cp - from;
 	float r = dot(v, dir) / len;
 	r = clamp(r, 0.0, 1.0);
 	vec4 col = texture2D(gradient, vec2(r, 0.0));
@@ -90,7 +88,6 @@ var radialGradientFS = `
 precision mediump float;
 #endif
 varying vec2 v_cp;
-uniform mat3 invmat;
 uniform sampler2D gradient;
 uniform vec2 from, to;
 uniform float radFrom, radTo;
@@ -99,13 +96,12 @@ bool isNaN(float v) {
   return v < 0.0 || 0.0 < v || v == 0.0 ? false : true;
 }
 void main() {
-	vec3 untf = vec3(v_cp, 1.0) * invmat;
 	float o_a = 0.5 * sqrt(
-		pow(-2.0*from.x*from.x+2.0*from.x*to.x+2.0*from.x*untf.x-2.0*to.x*untf.x-2.0*from.y*from.y+2.0*from.y*to.y+2.0*from.y*untf.y-2.0*to.y*untf.y+2.0*radFrom*radFrom-2.0*radFrom*radTo, 2.0)
-		-4.0*(from.x*from.x-2.0*from.x*untf.x+untf.x*untf.x+from.y*from.y-2.0*from.y*untf.y+untf.y*untf.y-radFrom*radFrom)
+		pow(-2.0*from.x*from.x+2.0*from.x*to.x+2.0*from.x*v_cp.x-2.0*to.x*v_cp.x-2.0*from.y*from.y+2.0*from.y*to.y+2.0*from.y*v_cp.y-2.0*to.y*v_cp.y+2.0*radFrom*radFrom-2.0*radFrom*radTo, 2.0)
+		-4.0*(from.x*from.x-2.0*from.x*v_cp.x+v_cp.x*v_cp.x+from.y*from.y-2.0*from.y*v_cp.y+v_cp.y*v_cp.y-radFrom*radFrom)
 		*(from.x*from.x-2.0*from.x*to.x+to.x*to.x+from.y*from.y-2.0*from.y*to.y+to.y*to.y-radFrom*radFrom+2.0*radFrom*radTo-radTo*radTo)
 	);
-	float o_b = (from.x*from.x-from.x*to.x-from.x*untf.x+to.x*untf.x+from.y*from.y-from.y*to.y-from.y*untf.y+to.y*untf.y-radFrom*radFrom+radFrom*radTo);
+	float o_b = (from.x*from.x-from.x*to.x-from.x*v_cp.x+to.x*v_cp.x+from.y*from.y-from.y*to.y-from.y*v_cp.y+to.y*v_cp.y-radFrom*radFrom+radFrom*radTo);
 	float o_c = (from.x*from.x-2.0*from.x*to.x+to.x*to.x+from.y*from.y-2.0*from.y*to.y+to.y*to.y-radFrom*radFrom+2.0*radFrom*radTo-radTo*radTo);
 	float o1 = (-o_a + o_b) / o_c;
 	float o2 = (o_a + o_b) / o_c;
@@ -135,12 +131,10 @@ precision mediump float;
 #endif
 varying vec2 v_cp;
 uniform vec2 imageSize;
-uniform mat3 invmat;
 uniform sampler2D image;
 uniform float globalAlpha;
 void main() {
-	vec3 untf = vec3(v_cp, 1.0) * invmat;
-	vec4 col = texture2D(image, mod(untf.xy / imageSize, 1.0));
+	vec4 col = texture2D(image, mod(v_cp / imageSize, 1.0));
 	col.a *= globalAlpha;
     gl_FragColor = col;
 }`
@@ -186,15 +180,13 @@ precision mediump float;
 varying vec2 v_cp;
 varying vec2 v_atc;
 varying vec2 v_texCoord;
-uniform mat3 invmat;
 uniform sampler2D gradient;
 uniform vec2 from, dir;
 uniform float len;
 uniform sampler2D alphaTex;
 uniform float globalAlpha;
 void main() {
-	vec3 untf = vec3(v_cp, 1.0) * invmat;
-	vec2 v = untf.xy - from;
+	vec2 v = v_cp - from;
 	float r = dot(v, dir) / len;
 	r = clamp(r, 0.0, 1.0);
     vec4 col = texture2D(gradient, vec2(r, 0.0));
@@ -219,7 +211,6 @@ precision mediump float;
 #endif
 varying vec2 v_cp;
 varying vec2 v_atc;
-uniform mat3 invmat;
 uniform sampler2D gradient;
 uniform vec2 from, to;
 uniform float radFrom, radTo;
@@ -229,13 +220,12 @@ bool isNaN(float v) {
   return v < 0.0 || 0.0 < v || v == 0.0 ? false : true;
 }
 void main() {
-	vec3 untf = vec3(v_cp, 1.0) * invmat;
 	float o_a = 0.5 * sqrt(
-		pow(-2.0*from.x*from.x+2.0*from.x*to.x+2.0*from.x*untf.x-2.0*to.x*untf.x-2.0*from.y*from.y+2.0*from.y*to.y+2.0*from.y*untf.y-2.0*to.y*untf.y+2.0*radFrom*radFrom-2.0*radFrom*radTo, 2.0)
-		-4.0*(from.x*from.x-2.0*from.x*untf.x+untf.x*untf.x+from.y*from.y-2.0*from.y*untf.y+untf.y*untf.y-radFrom*radFrom)
+		pow(-2.0*from.x*from.x+2.0*from.x*to.x+2.0*from.x*v_cp.x-2.0*to.x*v_cp.x-2.0*from.y*from.y+2.0*from.y*to.y+2.0*from.y*v_cp.y-2.0*to.y*v_cp.y+2.0*radFrom*radFrom-2.0*radFrom*radTo, 2.0)
+		-4.0*(from.x*from.x-2.0*from.x*v_cp.x+v_cp.x*v_cp.x+from.y*from.y-2.0*from.y*v_cp.y+v_cp.y*v_cp.y-radFrom*radFrom)
 		*(from.x*from.x-2.0*from.x*to.x+to.x*to.x+from.y*from.y-2.0*from.y*to.y+to.y*to.y-radFrom*radFrom+2.0*radFrom*radTo-radTo*radTo)
 	);
-	float o_b = (from.x*from.x-from.x*to.x-from.x*untf.x+to.x*untf.x+from.y*from.y-from.y*to.y-from.y*untf.y+to.y*untf.y-radFrom*radFrom+radFrom*radTo);
+	float o_b = (from.x*from.x-from.x*to.x-from.x*v_cp.x+to.x*v_cp.x+from.y*from.y-from.y*to.y-from.y*v_cp.y+to.y*v_cp.y-radFrom*radFrom+radFrom*radTo);
 	float o_c = (from.x*from.x-2.0*from.x*to.x+to.x*to.x+from.y*from.y-2.0*from.y*to.y+to.y*to.y-radFrom*radFrom+2.0*radFrom*radTo-radTo*radTo);
 	float o1 = (-o_a + o_b) / o_c;
 	float o2 = (o_a + o_b) / o_c;
@@ -268,13 +258,11 @@ precision mediump float;
 varying vec2 v_cp;
 varying vec2 v_atc;
 uniform vec2 imageSize;
-uniform mat3 invmat;
 uniform sampler2D image;
 uniform sampler2D alphaTex;
 uniform float globalAlpha;
 void main() {
-	vec3 untf = vec3(v_cp, 1.0) * invmat;
-    vec4 col = texture2D(image, mod(untf.xy / imageSize, 1.0));
+    vec4 col = texture2D(image, mod(v_cp / imageSize, 1.0));
     col.a *= texture2D(alphaTex, v_atc).a * globalAlpha;
 	gl_FragColor = col;
 }`
@@ -391,7 +379,6 @@ type linearGradientShader struct {
 	shaderProgram
 	Vertex      uint32
 	CanvasSize  int32
-	Invmat      int32
 	Gradient    int32
 	From        int32
 	Dir         int32
@@ -403,7 +390,6 @@ type radialGradientShader struct {
 	shaderProgram
 	Vertex      uint32
 	CanvasSize  int32
-	Invmat      int32
 	Gradient    int32
 	From        int32
 	To          int32
@@ -417,7 +403,6 @@ type imagePatternShader struct {
 	Vertex      uint32
 	CanvasSize  int32
 	ImageSize   int32
-	Invmat      int32
 	Image       int32
 	GlobalAlpha int32
 }
@@ -437,7 +422,6 @@ type linearGradientAlphaShader struct {
 	Vertex        uint32
 	AlphaTexCoord uint32
 	CanvasSize    int32
-	Invmat        int32
 	Gradient      int32
 	From          int32
 	Dir           int32
@@ -451,7 +435,6 @@ type radialGradientAlphaShader struct {
 	Vertex        uint32
 	AlphaTexCoord uint32
 	CanvasSize    int32
-	Invmat        int32
 	Gradient      int32
 	From          int32
 	To            int32
@@ -467,7 +450,6 @@ type imagePatternAlphaShader struct {
 	AlphaTexCoord uint32
 	CanvasSize    int32
 	ImageSize     int32
-	Invmat        int32
 	Image         int32
 	AlphaTex      int32
 	GlobalAlpha   int32
diff --git a/canvas_test.go b/canvas_test.go
index dc564cc..255bcda 100644
--- a/canvas_test.go
+++ b/canvas_test.go
@@ -543,14 +543,14 @@ func TestGradient(t *testing.T) {
 		cv.Rotate(math.Pi * 0.1)
 		cv.Translate(-50, -50)
 
-		lg := canvas.NewLinearGradient(10, 10, 40, 20)
+		lg := cv.NewLinearGradient(10, 10, 40, 20)
 		lg.AddColorStop(0, 0.5, 0, 0)
 		lg.AddColorStop(0.5, "#008000")
 		lg.AddColorStop(1, 0, 0, 128)
 		cv.SetFillStyle(lg)
 		cv.FillRect(0, 0, 50, 100)
 
-		rg := canvas.NewRadialGradient(75, 15, 10, 75, 75, 20)
+		rg := cv.NewRadialGradient(75, 15, 10, 75, 75, 20)
 		rg.AddColorStop(0, 1.0, 0, 0, 0.5)
 		rg.AddColorStop(0.5, "#00FF0080")
 		rg.AddColorStop(1, 0, 0, 255, 128)
diff --git a/testdata/Gradient.png b/testdata/Gradient.png
index 7b46ec7..cae9753 100755
Binary files a/testdata/Gradient.png and b/testdata/Gradient.png differ