waveshare2in13v2: Make sending image part of drawOpts

waveshare2in13v2/drawing.go

@@ -73,24 +73,23 @@ func (o *drawOpts) spec() drawSpec {
 }
 
 // sendImage sends an image to the controller after setting up the registers.
-// The area is in bytes on the horizontal axis.
-func sendImage(ctrl controller, cmd byte, area image.Rectangle, img *image1bit.VerticalLSB) {
-	if area.Empty() {
+func (o *drawOpts) sendImage(ctrl controller, cmd byte, spec *drawSpec) {
+	if spec.MemRect.Empty() {
 		return
 	}
 
-	setMemoryArea(ctrl, area)
+	setMemoryArea(ctrl, spec.MemRect)
 
 	ctrl.sendCommand(cmd)
 
-	rowData := make([]byte, area.Dx())
+	rowData := make([]byte, spec.MemRect.Dx())
 
-	for y := area.Min.Y; y < area.Max.Y; y++ {
+	for y := spec.MemRect.Min.Y; y < spec.MemRect.Max.Y; y++ {
 		for x := 0; x < len(rowData); x++ {
 			rowData[x] = 0
 
 			for bit := 0; bit < 8; bit++ {
-				if img.BitAt(((area.Min.X+x)*8)+bit, y) {
+				if o.buffer.BitAt(((spec.MemRect.Min.X+x)*8)+bit, y) {
 					rowData[x] |= 0x80 >> bit
 				}
 			}
@@ -117,6 +116,6 @@ func drawImage(ctrl controller, opts *drawOpts) {
 
 	// Keep the two buffers in sync.
 	for _, cmd := range commands {
-		sendImage(ctrl, cmd, s.MemRect, opts.buffer)
+		opts.sendImage(ctrl, cmd, &s)
 	}
 }

waveshare2in13v2/drawing_test.go

@@ -63,18 +63,23 @@ func TestSendImage(t *testing.T) {
 	for _, tc := range []struct {
 		name string
 		cmd  byte
-		area image.Rectangle
-		img  *image1bit.VerticalLSB
+		opts drawOpts
 		want []record
 	}{
 		{
 			name: "empty",
+			opts: drawOpts{
+				buffer: image1bit.NewVerticalLSB(image.Rectangle{}),
+			},
 		},
 		{
 			name: "partial",
 			cmd:  writeRAMBW,
-			area: image.Rect(2, 20, 4, 40),
-			img:  image1bit.NewVerticalLSB(image.Rect(0, 0, 64, 64)),
+			opts: drawOpts{
+				devSize: image.Pt(64, 64),
+				dstRect: image.Rect(16, 20, 32, 40),
+				buffer:  image1bit.NewVerticalLSB(image.Rect(0, 0, 64, 64)),
+			},
 			want: []record{
 				{cmd: dataEntryModeSetting, data: []byte{0x3}},
 				{cmd: setRAMXAddressStartEndPosition, data: []byte{2, 4 - 1}},
@@ -90,12 +95,15 @@ func TestSendImage(t *testing.T) {
 		{
 			name: "partial non-aligned",
 			cmd:  writeRAMRed,
-			area: image.Rect(2, 4, 6, 8),
-			img: func() *image1bit.VerticalLSB {
+			opts: drawOpts{
+				devSize: image.Pt(100, 64),
+				dstRect: image.Rect(17, 4, 41, 8),
+				buffer: func() *image1bit.VerticalLSB {
 					img := image1bit.NewVerticalLSB(image.Rect(0, 0, 64, 64))
 					draw.Src.Draw(img, image.Rect(17, 4, 41, 8), &image.Uniform{image1bit.On}, image.Point{})
 					return img
 				}(),
+			},
 			want: []record{
 				{cmd: dataEntryModeSetting, data: []byte{0x3}},
 				{cmd: setRAMXAddressStartEndPosition, data: []byte{2, 6 - 1}},
@@ -111,12 +119,15 @@ func TestSendImage(t *testing.T) {
 		{
 			name: "full",
 			cmd:  writeRAMBW,
-			area: image.Rect(0, 0, 10, 120),
-			img: func() *image1bit.VerticalLSB {
+			opts: drawOpts{
+				devSize: image.Pt(80, 120),
+				dstRect: image.Rect(0, 0, 80, 120),
+				buffer: func() *image1bit.VerticalLSB {
 					img := image1bit.NewVerticalLSB(image.Rect(0, 0, 80, 120))
 					draw.Src.Draw(img, image.Rect(0, 0, 80, 120), &image.Uniform{image1bit.On}, image.Point{})
 					return img
 				}(),
+			},
 			want: []record{
 				{cmd: dataEntryModeSetting, data: []byte{0x3}},
 				{cmd: setRAMXAddressStartEndPosition, data: []byte{0, 10 - 1}},
@@ -133,7 +144,9 @@ func TestSendImage(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			var got fakeController
 
-			sendImage(&got, tc.cmd, tc.area, tc.img)
+			spec := tc.opts.spec()
+
+			tc.opts.sendImage(&got, tc.cmd, &spec)
 
 			if diff := cmp.Diff([]record(got), tc.want, cmpopts.EquateEmpty(), cmp.AllowUnexported(record{})); diff != "" {
 				t.Errorf("sendImage() difference (-got +want):\n%s", diff)