From 566ca3cc75f9c6fbe1a015018d381cdbfbf1a2ad Mon Sep 17 00:00:00 2001
From: Takumi Sueda <puhitaku@gmail.com>
Date: Sat, 7 May 2022 16:09:51 +0900
Subject: [PATCH] Add tmemo_converter

---
 README.md                 |  1 +
 tmemo_converter/README.md | 16 +++++++++
 tmemo_converter/main.go   | 71 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 88 insertions(+)
 create mode 100644 tmemo_converter/README.md
 create mode 100644 tmemo_converter/main.go

diff --git a/README.md b/README.md
index 3e27869..a8ef23a 100644
--- a/README.md
+++ b/README.md
@@ -7,6 +7,7 @@
  - [read_keys_SH3.c](read_keys_SH3.c) Scan key matrix and return key name rewritten with C. nice performance
  - [x1](x1) Executable to analyze `[JHSBA]1` gen
  - [lcdbench](lcdbench) Benchmark fb0 fill and show results
+ - [tmemo_converter](tmemo_converter) Converts 手書き暗記メモ into PNGs (2G or older)
 
 
 ### License
diff --git a/tmemo_converter/README.md b/tmemo_converter/README.md
new file mode 100644
index 0000000..20c9f67
--- /dev/null
+++ b/tmemo_converter/README.md
@@ -0,0 +1,16 @@
+### Prerequisites
+ - Go 1.1x
+
+
+### Run
+
+```shell-session
+$ # Example 1
+$ go run main.go tmemo000.tmd
+
+$ # Example 2
+$ go run main.go tmemo000.tmd tmemo001.tmd
+
+$ # Example 3
+$ go run main.go *.tmd
+```
diff --git a/tmemo_converter/main.go b/tmemo_converter/main.go
new file mode 100644
index 0000000..65af373
--- /dev/null
+++ b/tmemo_converter/main.go
@@ -0,0 +1,71 @@
+package main
+
+import (
+	"fmt"
+	"image"
+	"image/color"
+	"image/png"
+	"io/ioutil"
+	"os"
+)
+
+const (
+	bytesPerPixel = 2
+	width         = 480
+	height        = 320
+	toolbarHeight = 16
+	actualHeight  = height - toolbarHeight
+
+	total = width * actualHeight * bytesPerPixel
+)
+
+func main() {
+	if len(os.Args) == 1 {
+		fmt.Printf("Usage: %s INPUT ...\n", os.Args[0])
+		fmt.Printf("Example: %s tmemo000.tmd tmemo001.tmd\n", os.Args[0])
+		os.Exit(0)
+	}
+
+	for _, a := range os.Args[1:] {
+		err := convert(a)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "failed to convert %s: %s\n", a, err)
+			os.Exit(1)
+		}
+	}
+}
+
+func convert(fn string) error {
+	raw, err := ioutil.ReadFile(fn)
+	if err != nil {
+		return fmt.Errorf("failed to read %s: %s", fn, err)
+	}
+
+	if len(raw) != total {
+		return fmt.Errorf("unexpected binary length: expect=%d, actual=%d", total, len(raw))
+	}
+
+	rgba := image.NewRGBA(image.Rect(0, 0, width, actualHeight))
+
+	for i := 0; i < width*actualHeight; i++ {
+		pixel := uint16(raw[i*2+1])<<8 + uint16(raw[i*2])
+		r := float64(pixel&0xf800>>11) * 255 / 31
+		g := float64(pixel&0x07e0>>5) * 255 / 63
+		b := float64(pixel&0x001f) * 255 / 31
+		rgba.SetRGBA(i%width, actualHeight-i/width, color.RGBA{R: uint8(r), G: uint8(g), B: uint8(b), A: 255})
+	}
+
+	newFn := fn + ".png"
+	out, err := os.Create(newFn)
+	if err != nil {
+		return fmt.Errorf("failed to create a file %s: %s", newFn, err)
+	}
+	defer out.Close()
+
+	err = png.Encode(out, rgba)
+	if err != nil {
+		return fmt.Errorf("failed to compress the image into PNG: %s", err)
+	}
+
+	return nil
+}