diff --git a/canvas.go b/canvas.go
index 8525dd4..cee2eb3 100644
--- a/canvas.go
+++ b/canvas.go
@@ -501,8 +501,6 @@ func (cv *Canvas) useShader(style *drawStyle) (vertexLoc uint32) {
 		length := dir.len()
 		dir = dir.divf(length)
 		gli.Uniform2f(lgr.canvasSize, float32(cv.fw), float32(cv.fh))
-		inv := cv.state.transform.invert().f32()
-		gli.UniformMatrix3fv(lgr.invmat, 1, false, &inv[0])
 		gli.Uniform2f(lgr.from, float32(from[0]), float32(from[1]))
 		gli.Uniform2f(lgr.dir, float32(dir[0]), float32(dir[1]))
 		gli.Uniform1f(lgr.len, float32(length))
@@ -521,8 +519,6 @@ func (cv *Canvas) useShader(style *drawStyle) (vertexLoc uint32) {
 		length := dir.len()
 		dir = dir.divf(length)
 		gli.Uniform2f(rgr.canvasSize, float32(cv.fw), float32(cv.fh))
-		inv := cv.state.transform.invert().f32()
-		gli.UniformMatrix3fv(rgr.invmat, 1, false, &inv[0])
 		gli.Uniform2f(rgr.from, float32(from[0]), float32(from[1]))
 		gli.Uniform2f(rgr.to, float32(to[0]), float32(to[1]))
 		gli.Uniform2f(rgr.dir, float32(dir[0]), float32(dir[1]))
@@ -538,8 +534,6 @@ func (cv *Canvas) useShader(style *drawStyle) (vertexLoc uint32) {
 		gli.ActiveTexture(gl_TEXTURE0)
 		gli.BindTexture(gl_TEXTURE_2D, img.tex)
 		gli.Uniform2f(ipr.canvasSize, float32(cv.fw), float32(cv.fh))
-		inv := cv.state.transform.invert().f32()
-		gli.UniformMatrix3fv(ipr.invmat, 1, false, &inv[0])
 		gli.Uniform2f(ipr.imageSize, float32(img.w), float32(img.h))
 		gli.Uniform1i(ipr.image, 0)
 		gli.Uniform1f(ipr.globalAlpha, float32(cv.state.globalAlpha))
@@ -566,8 +560,6 @@ func (cv *Canvas) useAlphaShader(style *drawStyle, alphaTexSlot int32) (vertexLo
 		length := dir.len()
 		dir = dir.divf(length)
 		gli.Uniform2f(lgar.canvasSize, float32(cv.fw), float32(cv.fh))
-		inv := cv.state.transform.invert().f32()
-		gli.UniformMatrix3fv(lgar.invmat, 1, false, &inv[0])
 		gli.Uniform2f(lgar.from, float32(from[0]), float32(from[1]))
 		gli.Uniform2f(lgar.dir, float32(dir[0]), float32(dir[1]))
 		gli.Uniform1f(lgar.len, float32(length))
@@ -587,8 +579,6 @@ func (cv *Canvas) useAlphaShader(style *drawStyle, alphaTexSlot int32) (vertexLo
 		length := dir.len()
 		dir = dir.divf(length)
 		gli.Uniform2f(rgar.canvasSize, float32(cv.fw), float32(cv.fh))
-		inv := cv.state.transform.invert().f32()
-		gli.UniformMatrix3fv(rgar.invmat, 1, false, &inv[0])
 		gli.Uniform2f(rgar.from, float32(from[0]), float32(from[1]))
 		gli.Uniform2f(rgar.to, float32(to[0]), float32(to[1]))
 		gli.Uniform2f(rgar.dir, float32(dir[0]), float32(dir[1]))
@@ -605,8 +595,6 @@ func (cv *Canvas) useAlphaShader(style *drawStyle, alphaTexSlot int32) (vertexLo
 		gli.ActiveTexture(gl_TEXTURE0)
 		gli.BindTexture(gl_TEXTURE_2D, img.tex)
 		gli.Uniform2f(ipar.canvasSize, float32(cv.fw), float32(cv.fh))
-		inv := cv.state.transform.invert().f32()
-		gli.UniformMatrix3fv(ipar.invmat, 1, false, &inv[0])
 		gli.Uniform2f(ipar.imageSize, float32(img.w), float32(img.h))
 		gli.Uniform1i(ipar.image, 0)
 		gli.Uniform1i(ipar.alphaTex, alphaTexSlot)
diff --git a/canvas_test.go b/canvas_test.go
index cf8bc19..e34bcae 100644
--- a/canvas_test.go
+++ b/canvas_test.go
@@ -3,6 +3,7 @@ package canvas_test
 import (
 	"fmt"
 	"image/png"
+	"math"
 	"os"
 	"runtime"
 	"strings"
@@ -519,3 +520,52 @@ func TestTransform2(t *testing.T) {
 		cv.Stroke()
 	})
 }
+
+func TestImage(t *testing.T) {
+	run(t, func(cv *canvas.Canvas) {
+		cv.DrawImage("testdata/cat.jpg", 5, 5, 40, 40)
+		cv.DrawImage("testdata/cat.jpg", 100, 100, 100, 100, 55, 55, 40, 40)
+		cv.Save()
+		cv.Translate(75, 25)
+		cv.Rotate(math.Pi / 2)
+		cv.Translate(-20, -20)
+		cv.DrawImage("testdata/cat.jpg", 0, 0, 40, 40)
+		cv.Restore()
+		cv.SetTransform(1, 0, 0.2, 1, 0, 0)
+		cv.DrawImage("testdata/cat.jpg", -8, 55, 40, 40)
+	})
+}
+
+func TestGradient(t *testing.T) {
+	run(t, func(cv *canvas.Canvas) {
+		cv.Translate(50, 50)
+		cv.Scale(0.8, 0.7)
+		cv.Rotate(math.Pi * 0.1)
+		cv.Translate(-50, -50)
+
+		lg := canvas.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.AddColorStop(0, 1.0, 0, 0, 0.5)
+		rg.AddColorStop(0.5, "#00FF0080")
+		rg.AddColorStop(1, 0, 0, 255, 128)
+		cv.SetFillStyle(rg)
+		cv.FillRect(50, 0, 50, 100)
+	})
+}
+
+func TestImagePattern(t *testing.T) {
+	run(t, func(cv *canvas.Canvas) {
+		cv.Translate(50, 50)
+		cv.Scale(0.95, 1.05)
+		cv.Rotate(-math.Pi * 0.1)
+
+		cv.SetFillStyle("testdata/cat.jpg")
+		cv.FillRect(-40, -40, 80, 80)
+	})
+}
diff --git a/shaders.go b/shaders.go
index 14f2c76..6274e3b 100644
--- a/shaders.go
+++ b/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, dir;
 uniform float radFrom, radTo;
@@ -100,13 +97,12 @@ 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;
@@ -136,12 +132,10 @@ 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;
 }`
@@ -187,15 +181,13 @@ 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.xy - from;
 	float r = dot(v, dir) / len;
 	r = clamp(r, 0.0, 1.0);
     vec4 col = texture2D(gradient, vec2(r, 0.0));
@@ -220,7 +212,6 @@ precision mediump float;
 #endif
 varying vec2 v_cp;
 varying vec2 v_atc;
-uniform mat3 invmat;
 uniform sampler2D gradient;
 uniform vec2 from, to, dir;
 uniform float radFrom, radTo;
@@ -231,13 +222,12 @@ 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;
@@ -270,13 +260,11 @@ 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;
 }`
diff --git a/testdata/Gradient.png b/testdata/Gradient.png
new file mode 100755
index 0000000..7b46ec7
Binary files /dev/null and b/testdata/Gradient.png differ
diff --git a/testdata/Image.png b/testdata/Image.png
new file mode 100755
index 0000000..d6a35e5
Binary files /dev/null and b/testdata/Image.png differ
diff --git a/testdata/ImagePattern.png b/testdata/ImagePattern.png
new file mode 100755
index 0000000..0b45986
Binary files /dev/null and b/testdata/ImagePattern.png differ
diff --git a/testdata/cat.jpg b/testdata/cat.jpg
new file mode 100755
index 0000000..27bcece
Binary files /dev/null and b/testdata/cat.jpg differ