mirror of https://github.com/periph/devices
waveshare213v2: Add support for partial drawing
When the destination rectangle didn't start at (0,0) or cover the whole display the Dev.Draw function would continue to update the display in full. Obviously that didn't result in a good output. This change updates the drawing logic to only update the affected area (aligned to whole bytes on the horizontal axis) and limits the amount of transferred data to the minimum needed to cover the destination rectangle. The calculation of the various offsets as well as the function sending the image data are written to support unittesting. Signed-off-by: Michael Hanselmann <public@hansmi.ch>pull/38/head
Michael Hanselmann
4 years ago
parent
1ade23a46c
commit
fae68919b9
@ -0,0 +1,130 @@
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// Copyright 2021 The Periph Authors. All rights reserved.
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// Use of this source code is governed under the Apache License, Version 2.0
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// that can be found in the LICENSE file.
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package waveshare2in13v2
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import (
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"image"
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"image/draw"
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"periph.io/x/devices/v3/ssd1306/image1bit"
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)
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type controller interface {
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sendCommand(byte)
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sendData([]byte)
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}
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// setMemoryArea configures the target drawing area (horizontal is in bytes,
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// vertical in pixels).
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func setMemoryArea(ctrl controller, area image.Rectangle) {
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ctrl.sendCommand(dataEntryModeSetting)
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ctrl.sendData([]byte{
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// Y increment, X increment; update address counter in X direction
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0b011,
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})
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ctrl.sendCommand(setRAMXAddressStartEndPosition)
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ctrl.sendData([]byte{
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// Start
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byte(area.Min.X),
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// End
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byte(area.Max.X - 1),
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})
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ctrl.sendCommand(setRAMYAddressStartEndPosition)
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ctrl.sendData([]byte{
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// Start
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byte(area.Min.Y % 0xFF),
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byte(area.Min.Y / 0xFF),
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// End
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byte((area.Max.Y - 1) % 0xFF),
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byte((area.Max.Y - 1) / 0xFF),
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})
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ctrl.sendCommand(setRAMXAddressCounter)
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ctrl.sendData([]byte{byte(area.Min.X)})
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ctrl.sendCommand(setRAMYAddressCounter)
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ctrl.sendData([]byte{
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byte(area.Min.Y % 0xFF),
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byte(area.Min.Y / 0xFF),
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})
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}
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type drawOpts struct {
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cmd byte
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devSize image.Point
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dstRect image.Rectangle
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src image.Image
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srcPts image.Point
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}
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type drawSpec struct {
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// Destination on display in pixels, normalized to fit into actual size.
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DstRect image.Rectangle
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// Size of memory area to write; horizontally in bytes, vertically in
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// pixels.
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MemRect image.Rectangle
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// Size of image buffer, horizontally aligned to multiples of 8 pixels.
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BufferSize image.Point
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// Destination rectangle within image buffer.
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BufferRect image.Rectangle
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}
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func (o *drawOpts) spec() drawSpec {
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s := drawSpec{
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DstRect: image.Rectangle{Max: o.devSize}.Intersect(o.dstRect),
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}
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s.MemRect = image.Rect(
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s.DstRect.Min.X/8, s.DstRect.Min.Y,
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(s.DstRect.Max.X+7)/8, s.DstRect.Max.Y,
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)
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s.BufferSize = image.Pt(s.MemRect.Dx()*8, s.MemRect.Dy())
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s.BufferRect = image.Rectangle{
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Min: image.Point{X: s.DstRect.Min.X - (s.MemRect.Min.X * 8)},
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Max: image.Point{Y: s.DstRect.Dy()},
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}
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s.BufferRect.Max.X = s.BufferRect.Min.X + s.DstRect.Dx()
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return s
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}
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// drawImage sends an image to the controller after setting up the registers.
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func drawImage(ctrl controller, opts *drawOpts) {
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s := opts.spec()
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if s.MemRect.Empty() {
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return
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}
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img := image1bit.NewVerticalLSB(image.Rectangle{Max: s.BufferSize})
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draw.Src.Draw(img, s.BufferRect, opts.src, opts.srcPts)
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setMemoryArea(ctrl, s.MemRect)
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ctrl.sendCommand(opts.cmd)
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rowData := make([]byte, s.MemRect.Dx())
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for y := 0; y < img.Bounds().Dy(); y++ {
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for x := 0; x < len(rowData); x++ {
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rowData[x] = 0
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for bit := 0; bit < 8; bit++ {
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if img.BitAt((x*8)+bit, y) {
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rowData[x] |= 0x80 >> bit
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}
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}
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}
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ctrl.sendData(rowData)
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}
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}
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@ -0,0 +1,146 @@
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// Copyright 2021 The Periph Authors. All rights reserved.
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// Use of this source code is governed under the Apache License, Version 2.0
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// that can be found in the LICENSE file.
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package waveshare2in13v2
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import (
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"bytes"
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"image"
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"testing"
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"github.com/google/go-cmp/cmp"
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"github.com/google/go-cmp/cmp/cmpopts"
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"periph.io/x/devices/v3/ssd1306/image1bit"
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)
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type record struct {
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cmd byte
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data []byte
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}
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type fakeController []record
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func (r *fakeController) sendCommand(cmd byte) {
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*r = append(*r, record{
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cmd: cmd,
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})
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}
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func (r *fakeController) sendData(data []byte) {
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cur := &(*r)[len(*r)-1]
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cur.data = append(cur.data, data...)
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}
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func TestDrawSpec(t *testing.T) {
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for _, tc := range []struct {
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name string
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opts drawOpts
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want drawSpec
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}{
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{
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name: "empty",
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},
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{
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name: "smaller than display",
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opts: drawOpts{
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devSize: image.Pt(100, 200),
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dstRect: image.Rect(17, 4, 25, 8),
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},
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want: drawSpec{
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DstRect: image.Rect(17, 4, 25, 8),
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MemRect: image.Rect(2, 4, 4, 8),
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BufferSize: image.Pt(16, 4),
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BufferRect: image.Rect(1, 0, 9, 4),
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},
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},
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{
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name: "larger than display",
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opts: drawOpts{
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devSize: image.Pt(100, 200),
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dstRect: image.Rect(-20, 50, 125, 300),
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},
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want: drawSpec{
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DstRect: image.Rect(0, 50, 100, 200),
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MemRect: image.Rect(0, 50, 13, 200),
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BufferSize: image.Pt(13*8, 150),
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BufferRect: image.Rect(0, 0, 100, 150),
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},
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},
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} {
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t.Run(tc.name, func(t *testing.T) {
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got := tc.opts.spec()
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if diff := cmp.Diff(got, tc.want, cmpopts.EquateEmpty()); diff != "" {
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t.Errorf("spec() difference (-got +want):\n%s", diff)
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}
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})
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}
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}
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func TestDrawImage(t *testing.T) {
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for _, tc := range []struct {
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name string
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opts drawOpts
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want []record
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}{
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{
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name: "empty",
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opts: drawOpts{
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src: &image.Uniform{image1bit.On},
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},
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},
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{
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name: "partial",
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opts: drawOpts{
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cmd: writeRAMBW,
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devSize: image.Pt(64, 64),
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dstRect: image.Rect(17, 4, 41, 8),
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src: &image.Uniform{image1bit.On},
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srcPts: image.Pt(0, 0),
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},
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want: []record{
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{cmd: dataEntryModeSetting, data: []byte{0x3}},
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{cmd: setRAMXAddressStartEndPosition, data: []byte{2, 6 - 1}},
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{cmd: setRAMYAddressStartEndPosition, data: []byte{4, 0, 8 - 1, 0}},
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{cmd: setRAMXAddressCounter, data: []byte{2}},
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{cmd: setRAMYAddressCounter, data: []byte{4, 0}},
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{
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cmd: writeRAMBW,
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data: bytes.Repeat([]byte{0x7f, 0xff, 0xff, 0x80}, 4),
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},
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},
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},
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{
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name: "full",
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opts: drawOpts{
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cmd: writeRAMBW,
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devSize: image.Pt(80, 120),
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dstRect: image.Rect(0, 0, 80, 120),
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src: &image.Uniform{image1bit.On},
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srcPts: image.Pt(33, 44),
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},
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want: []record{
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{cmd: dataEntryModeSetting, data: []byte{0x3}},
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{cmd: setRAMXAddressStartEndPosition, data: []byte{0, 10 - 1}},
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{cmd: setRAMYAddressStartEndPosition, data: []byte{0, 0, 120 - 1, 0}},
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{cmd: setRAMXAddressCounter, data: []byte{0}},
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{cmd: setRAMYAddressCounter, data: []byte{0, 0}},
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{
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cmd: writeRAMBW,
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data: bytes.Repeat([]byte{0xff}, 80/8*120),
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},
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},
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},
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} {
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t.Run(tc.name, func(t *testing.T) {
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var got fakeController
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drawImage(&got, &tc.opts)
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if diff := cmp.Diff([]record(got), tc.want, cmpopts.EquateEmpty(), cmp.AllowUnexported(record{})); diff != "" {
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t.Errorf("drawImage() difference (-got +want):\n%s", diff)
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}
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})
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}
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}
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@ -1,38 +0,0 @@
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// Copyright 2021 The Periph Authors. All rights reserved.
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// Use of this source code is governed under the Apache License, Version 2.0
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// that can be found in the LICENSE file.
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package waveshare2in13v2
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import (
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"fmt"
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"testing"
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)
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func TestDataDimensions(t *testing.T) {
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for _, tc := range []struct {
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opts *Opts
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wantHeight int
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wantWidth int
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}{
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{opts: &Opts{Width: 0, Height: 0}},
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{
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opts: &Opts{Height: 48, Width: 16},
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wantHeight: 48,
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wantWidth: 2,
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},
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{
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opts: &Opts{Height: 250, Width: 122},
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wantHeight: 250,
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wantWidth: 16,
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},
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} {
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t.Run(fmt.Sprintf("%+v", *tc.opts), func(t *testing.T) {
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gotHeight, gotWidth := dataDimensions(tc.opts)
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if !(gotHeight == tc.wantHeight && gotWidth == tc.wantWidth) {
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t.Errorf("dataDimensions(%#v) returned %d, %d; want %d, %d", tc.opts, gotHeight, gotWidth, tc.wantHeight, tc.wantWidth)
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}
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})
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}
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}
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