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example/convert-to-nia: allow 16-bit PNG output

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This commit is contained in:
Nigel Tao
2025-06-23 09:51:31 +10:00
parent bb25727729
commit 67e9078eab
8 changed files with 231 additions and 38 deletions
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17
example/convert-to-nia/convert-to-nia.c
View File

@@ -159,8 +159,6 @@ static const char* g_usage =
"Using -16 produces 16 bits per channel. For NIA/NIE output, this is the\n"
"\"bn8\" version-and-configuration in the spec.\n"
"\n"
"Combining -u and -16 is unsupported.\n"
"\n"
"The -fail-if-unsandboxed flag causes the program to exit if it does not\n"
"self-impose a sandbox. On Linux, it self-imposes a SECCOMP_MODE_STRICT\n"
"sandbox, regardless of whether this flag was set.";
@@ -318,8 +316,6 @@ parse_flags(int argc, char** argv) {
if (num_one_of > 1) {
return g_usage;
} else if (g_flags.output_uncompressed_png && g_flags.bit_depth_16) {
return "main: combining -u and -16 is unsupported";
}
g_flags.output_nia_or_crc32_digest =
(num_one_of == 0) || g_flags.output_crc32_digest;
@@ -787,16 +783,17 @@ my_uncompng_write_func(void* context,
bool //
print_uncompressed_png_frame() {
if (g_flags.bit_depth_16) {
return false;
}
uint32_t pixfmt = 0;
if (g_pixfmt_is_gray) {
pixfmt = UNCOMPNG__PIXEL_FORMAT__YXXX;
pixfmt = g_flags.bit_depth_16 ? UNCOMPNG__PIXEL_FORMAT__YXXX_4X16LE
: UNCOMPNG__PIXEL_FORMAT__YXXX;
} else if (wuffs_base__pixel_buffer__is_opaque(&g_pixbuf)) {
pixfmt = UNCOMPNG__PIXEL_FORMAT__BGRX;
pixfmt = g_flags.bit_depth_16 ? UNCOMPNG__PIXEL_FORMAT__BGRX_4X16LE
: UNCOMPNG__PIXEL_FORMAT__BGRX;
} else {
pixfmt = UNCOMPNG__PIXEL_FORMAT__BGRA_NONPREMUL;
pixfmt = g_flags.bit_depth_16
? UNCOMPNG__PIXEL_FORMAT__BGRA_NONPREMUL_4X16LE
: UNCOMPNG__PIXEL_FORMAT__BGRA_NONPREMUL;
}
uint32_t w = wuffs_base__pixel_config__width(&g_pixbuf.pixcfg);

107
lib/uncompng/uncompng.go
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@@ -51,25 +51,27 @@ import (
type ColorType byte
const (
// ColorTypeGray means 1 byte per pixel.
// ColorTypeGray means 1 byte per pixel (or 2 for Depth16, big-endian).
//
// This matches Go's image.Gray.Pix layout.
// This matches Go's image.Gray.Pix (or Gray16, for Depth16) layout.
ColorTypeGray = ColorType(1)
// ColorTypeRGBX means 4 bytes per pixel. Red, Green, Blue and the 4th
// channel is ignored.
// ColorTypeRGBX means 4 bytes per pixel (or 8 for Depth16, big-endian).
// Red, Green, Blue and the 4th channel is ignored.
//
// This matches Go's image.RGBA.Pix and image.NRGBA.Pix layouts, provided
// that all of the pixels' alpha values are 0xFF.
// This matches Go's image.RGBA.Pix and image.NRGBA.Pix layouts (or RGBA64
// or NRGBA64, for Depth16), provided that all of the pixels' alpha values
// are 0xFF (or 0xFFFF, for Depth16).
ColorTypeRGBX = ColorType(2)
// ColorTypeRGBX means 4 bytes per pixel. Red, Green, Blue and Alpha. RGB
// uses non-premultiplied alpha.
// ColorTypeRGBX means 4 bytes per pixel (or 8 for Depth16, big-endian).
// Red, Green, Blue and Alpha. RGB uses non-premultiplied alpha.
//
// This matches Go's image.NRGBA.Pix layout. If all of the pixels' alpha
// values are 0xFF then either ColorTypeRGBX or ColorTypeNRGBA will produce
// the same PNG output (in terms of pixels) but smaller (ColorTypeRGBX) or
// larger (ColorTypeNRGBA) output in terms of byte count.
// This matches Go's image.NRGBA.Pix layout (or NRGBA64, for Depth16). If
// all of the pixels' alpha values are 0xFF (or 0xFFFF, for Depth16) then
// either ColorTypeRGBX or ColorTypeNRGBA will produce the same PNG output
// (in terms of pixels) but smaller (ColorTypeRGBX) or larger
// (ColorTypeNRGBA) output in terms of byte count.
ColorTypeNRGBA = ColorType(3)
)
@@ -87,13 +89,15 @@ func (c ColorType) pngFileFormatEncoding() byte {
}
// Depth is the number of bits per channel.
//
// This package only supports a depth of 8. In the future, it might also
// support a depth of 16.
type Depth byte
const (
// Depth8 means one byte per pixel.
Depth8 = Depth(8)
// Depth16 means two bytes per pixel. Values are big-endian like the Go
// standard library's Gray16, RGBA64 and NRGBA64 image types.
Depth16 = Depth(16)
)
// Encoder is an opaque type that can convert a slice of pixel data to
@@ -189,11 +193,13 @@ const (
// Encode writes the pixel data to w. It makes no allocations above whatever
// w.Write makes, if any.
//
// pix holds the pixel data, either 1 or 4 bytes per pixel depending on the
// colorType. width and height are measured in pixels. stride is measured in
// bytes. depth must be Depth8 although this might be relaxed in the future.
// pix holds the pixel data, either 1 or 4 bytes per pixel (doubled for
// Depth16) depending on the colorType. width and height are measured in
// pixels. stride is measured in bytes. depth must be either Depth8 or Depth16.
func (e *Encoder) Encode(w io.Writer, pix []byte, width int, height int, stride int, depth Depth, colorType ColorType) error {
if (width < 0) || (height < 0) || (depth != Depth8) || (colorType.pngFileFormatEncoding() == 0xFF) {
if (width < 0) || (height < 0) ||
((depth != Depth8) && (depth != Depth16)) ||
(colorType.pngFileFormatEncoding() == 0xFF) {
return errors.New("uncompng: invalid argument")
} else if (width > 0xFFFFFF) || (height > 0xFFFFFF) {
return errors.New("uncompng: unsupported image size")
@@ -214,8 +220,8 @@ func (e *Encoder) Encode(w io.Writer, pix []byte, width int, height int, stride
row := pix[y*stride:]
switch colorType {
case ColorTypeGray:
switch ColorType(depth) | colorType {
case 0x08 | ColorTypeGray:
row = row[:1*width]
for x := 0; x < width; x++ {
if (ej + 1) > ejMax {
@@ -229,7 +235,7 @@ func (e *Encoder) Encode(w io.Writer, pix []byte, width int, height int, stride
row = row[1:]
}
case ColorTypeRGBX:
case 0x08 | ColorTypeRGBX:
row = row[:4*width]
for x := 0; x < width; x++ {
if (ej + 3) > ejMax {
@@ -245,7 +251,7 @@ func (e *Encoder) Encode(w io.Writer, pix []byte, width int, height int, stride
row = row[4:]
}
case ColorTypeNRGBA:
case 0x08 | ColorTypeNRGBA:
row = row[:4*width]
for x := 0; x < width; x++ {
if (ej + 4) > ejMax {
@@ -261,6 +267,61 @@ func (e *Encoder) Encode(w io.Writer, pix []byte, width int, height int, stride
ej += 4
row = row[4:]
}
case 0x10 | ColorTypeGray:
row = row[:2*width]
for x := 0; x < width; x++ {
if (ej + 2) > ejMax {
if err := e.flush(w, ej, false); err != nil {
return err
}
ej = eiLater
}
e.buf[ej+0] = row[0]
e.buf[ej+1] = row[1]
ej += 2
row = row[2:]
}
case 0x10 | ColorTypeRGBX:
row = row[:8*width]
for x := 0; x < width; x++ {
if (ej + 6) > ejMax {
if err := e.flush(w, ej, false); err != nil {
return err
}
ej = eiLater
}
e.buf[ej+0] = row[0]
e.buf[ej+1] = row[1]
e.buf[ej+2] = row[2]
e.buf[ej+3] = row[3]
e.buf[ej+4] = row[4]
e.buf[ej+5] = row[5]
ej += 6
row = row[8:]
}
case 0x10 | ColorTypeNRGBA:
row = row[:8*width]
for x := 0; x < width; x++ {
if (ej + 8) > ejMax {
if err := e.flush(w, ej, false); err != nil {
return err
}
ej = eiLater
}
e.buf[ej+0] = row[0]
e.buf[ej+1] = row[1]
e.buf[ej+2] = row[2]
e.buf[ej+3] = row[3]
e.buf[ej+4] = row[4]
e.buf[ej+5] = row[5]
e.buf[ej+6] = row[6]
e.buf[ej+7] = row[7]
ej += 8
row = row[8:]
}
}
}

23
lib/uncompng/uncompng_test.go
View File

@@ -28,17 +28,32 @@ func encodeImage(w io.Writer, src image.Image) error {
case *image.Gray:
return e.Encode(w, src.Pix, b.Dx(), b.Dy(), src.Stride, Depth8, ColorTypeGray)
case *image.Gray16:
return e.Encode(w, src.Pix, b.Dx(), b.Dy(), src.Stride, Depth16, ColorTypeGray)
case *image.RGBA:
if src.Opaque() {
return e.Encode(w, src.Pix, b.Dx(), b.Dy(), src.Stride, Depth8, ColorTypeRGBX)
}
case *image.RGBA64:
if src.Opaque() {
return e.Encode(w, src.Pix, b.Dx(), b.Dy(), src.Stride, Depth16, ColorTypeRGBX)
}
case *image.NRGBA:
if src.Opaque() {
return e.Encode(w, src.Pix, b.Dx(), b.Dy(), src.Stride, Depth8, ColorTypeRGBX)
} else {
return e.Encode(w, src.Pix, b.Dx(), b.Dy(), src.Stride, Depth8, ColorTypeNRGBA)
}
case *image.NRGBA64:
if src.Opaque() {
return e.Encode(w, src.Pix, b.Dx(), b.Dy(), src.Stride, Depth16, ColorTypeRGBX)
} else {
return e.Encode(w, src.Pix, b.Dx(), b.Dy(), src.Stride, Depth16, ColorTypeNRGBA)
}
}
tmp := image.NewNRGBA(b)
@@ -50,16 +65,24 @@ func getPix(m image.Image) []byte {
switch m := m.(type) {
case *image.Gray:
return m.Pix
case *image.Gray16:
return m.Pix
case *image.RGBA:
return m.Pix
case *image.RGBA64:
return m.Pix
case *image.NRGBA:
return m.Pix
case *image.NRGBA64:
return m.Pix
}
return nil
}
func TestRoundTrip(tt *testing.T) {
testCases := []string{
"36.png",
"49.png",
"bricks-color.png",
"bricks-gray.png",
"harvesters.png",

117
snippet/uncompng.c
View File

@@ -36,16 +36,24 @@
#include <stddef.h>
#include <stdint.h>
// clang-format off
// UNCOMPNG__PIXEL_FORMAT__ETC are the valid pixel_format values to pass to
// uncompng__encode.
//
// These constants' values are the same as the corresponding Wuffs definitions,
// after replacing the name's "WUFFS_BASE" prefix with "UNCOMPNG". This file is
// stand-alone. It does not #include any Wuffs code.
#define UNCOMPNG__PIXEL_FORMAT__Y 0x20000008
#define UNCOMPNG__PIXEL_FORMAT__YXXX 0x30008888
#define UNCOMPNG__PIXEL_FORMAT__BGRA_NONPREMUL 0x81008888
#define UNCOMPNG__PIXEL_FORMAT__BGRX 0x90008888
#define UNCOMPNG__PIXEL_FORMAT__Y 0x20000008
#define UNCOMPNG__PIXEL_FORMAT__Y_16LE 0x2000000B
#define UNCOMPNG__PIXEL_FORMAT__YXXX 0x30008888
#define UNCOMPNG__PIXEL_FORMAT__YXXX_4X16LE 0x3000BBBB
#define UNCOMPNG__PIXEL_FORMAT__BGRA_NONPREMUL 0x81008888
#define UNCOMPNG__PIXEL_FORMAT__BGRA_NONPREMUL_4X16LE 0x8100BBBB
#define UNCOMPNG__PIXEL_FORMAT__BGRX 0x90008888
#define UNCOMPNG__PIXEL_FORMAT__BGRX_4X16LE 0x9000BBBB
// clang-format on
// UNCOMPNG__RESULT__ETC can be returned by uncompng__encode. write_func can
// also return its own negative error codes, which are passed on.
@@ -185,23 +193,40 @@ uncompng__private_impl_initialize_buffer(uint32_t width,
uncompng__private_impl_buffer[0x0015] = (uint8_t)(height >> 16);
uncompng__private_impl_buffer[0x0016] = (uint8_t)(height >> 8);
uncompng__private_impl_buffer[0x0017] = (uint8_t)(height >> 0);
uncompng__private_impl_buffer[0x0018] = 8;
uint8_t depth;
uint8_t color_type;
switch (pixel_format) {
case UNCOMPNG__PIXEL_FORMAT__Y:
case UNCOMPNG__PIXEL_FORMAT__YXXX:
depth = 8;
color_type = 0;
break;
case UNCOMPNG__PIXEL_FORMAT__BGRA_NONPREMUL:
depth = 8;
color_type = 6;
break;
case UNCOMPNG__PIXEL_FORMAT__BGRX:
depth = 8;
color_type = 2;
break;
case UNCOMPNG__PIXEL_FORMAT__Y_16LE:
case UNCOMPNG__PIXEL_FORMAT__YXXX_4X16LE:
depth = 16;
color_type = 0;
break;
case UNCOMPNG__PIXEL_FORMAT__BGRA_NONPREMUL_4X16LE:
depth = 16;
color_type = 6;
break;
case UNCOMPNG__PIXEL_FORMAT__BGRX_4X16LE:
depth = 16;
color_type = 2;
break;
default:
return;
}
uncompng__private_impl_buffer[0x0018] = depth;
uncompng__private_impl_buffer[0x0019] = color_type;
uncompng__private_impl_buffer[0x001A] = 0;
uncompng__private_impl_buffer[0x001B] = 0;
@@ -413,6 +438,22 @@ uncompng__private_impl_do_encode(int (*write_func)(void* context,
}
break;
case UNCOMPNG__PIXEL_FORMAT__Y_16LE:
for (uint32_t x = 0; x < width; x++) {
if ((ej + 2) > ej_max) {
int err =
uncompng__private_impl_flush(write_func, context, ej, false);
if (err != 0) {
return err;
}
ej = ei_later;
}
uncompng__private_impl_buffer[ej++] = row[1];
uncompng__private_impl_buffer[ej++] = row[0];
row += 2;
}
break;
case UNCOMPNG__PIXEL_FORMAT__YXXX:
for (uint32_t x = 0; x < width; x++) {
if ((ej + 1) > ej_max) {
@@ -428,6 +469,22 @@ uncompng__private_impl_do_encode(int (*write_func)(void* context,
}
break;
case UNCOMPNG__PIXEL_FORMAT__YXXX_4X16LE:
for (uint32_t x = 0; x < width; x++) {
if ((ej + 2) > ej_max) {
int err =
uncompng__private_impl_flush(write_func, context, ej, false);
if (err != 0) {
return err;
}
ej = ei_later;
}
uncompng__private_impl_buffer[ej++] = row[1];
uncompng__private_impl_buffer[ej++] = row[0];
row += 8;
}
break;
case UNCOMPNG__PIXEL_FORMAT__BGRA_NONPREMUL:
for (uint32_t x = 0; x < width; x++) {
if ((ej + 4) > ej_max) {
@@ -446,6 +503,28 @@ uncompng__private_impl_do_encode(int (*write_func)(void* context,
}
break;
case UNCOMPNG__PIXEL_FORMAT__BGRA_NONPREMUL_4X16LE:
for (uint32_t x = 0; x < width; x++) {
if ((ej + 8) > ej_max) {
int err =
uncompng__private_impl_flush(write_func, context, ej, false);
if (err != 0) {
return err;
}
ej = ei_later;
}
uncompng__private_impl_buffer[ej++] = row[5];
uncompng__private_impl_buffer[ej++] = row[4];
uncompng__private_impl_buffer[ej++] = row[3];
uncompng__private_impl_buffer[ej++] = row[2];
uncompng__private_impl_buffer[ej++] = row[1];
uncompng__private_impl_buffer[ej++] = row[0];
uncompng__private_impl_buffer[ej++] = row[7];
uncompng__private_impl_buffer[ej++] = row[6];
row += 8;
}
break;
case UNCOMPNG__PIXEL_FORMAT__BGRX:
for (uint32_t x = 0; x < width; x++) {
if ((ej + 3) > ej_max) {
@@ -463,6 +542,26 @@ uncompng__private_impl_do_encode(int (*write_func)(void* context,
}
break;
case UNCOMPNG__PIXEL_FORMAT__BGRX_4X16LE:
for (uint32_t x = 0; x < width; x++) {
if ((ej + 6) > ej_max) {
int err =
uncompng__private_impl_flush(write_func, context, ej, false);
if (err != 0) {
return err;
}
ej = ei_later;
}
uncompng__private_impl_buffer[ej++] = row[5];
uncompng__private_impl_buffer[ej++] = row[4];
uncompng__private_impl_buffer[ej++] = row[3];
uncompng__private_impl_buffer[ej++] = row[2];
uncompng__private_impl_buffer[ej++] = row[1];
uncompng__private_impl_buffer[ej++] = row[0];
row += 8;
}
break;
default:
return UNCOMPNG__RESULT__INVALID_ARGUMENT;
}
@@ -490,11 +589,19 @@ uncompng__encode(int (*write_func)(void* context,
case UNCOMPNG__PIXEL_FORMAT__Y:
bytes_per_pixel = 1u;
break;
case UNCOMPNG__PIXEL_FORMAT__Y_16LE:
bytes_per_pixel = 2u;
break;
case UNCOMPNG__PIXEL_FORMAT__YXXX:
case UNCOMPNG__PIXEL_FORMAT__BGRA_NONPREMUL:
case UNCOMPNG__PIXEL_FORMAT__BGRX:
bytes_per_pixel = 4u;
break;
case UNCOMPNG__PIXEL_FORMAT__YXXX_4X16LE:
case UNCOMPNG__PIXEL_FORMAT__BGRA_NONPREMUL_4X16LE:
case UNCOMPNG__PIXEL_FORMAT__BGRX_4X16LE:
bytes_per_pixel = 8u;
break;
default:
return UNCOMPNG__RESULT__INVALID_ARGUMENT;
}

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3
test/data/README.md
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@@ -38,6 +38,9 @@ The non-ascii directory holds trivial UTF-8 (but not ASCII) text files.
---
`36.png` and `49.png` are simple, artificially generated images. The generation
script is `gen-36-49.go` from https://github.com/nigeltao/etc2
`DCI-P3-D65.icc` comes from
[color.org](https://www.color.org/chardata/rgb/DCIP3.xalter).
`DCI-P3-D65.icc.zlib` is a zlib-compresion of that, created by Go's standard

2
test/nia-checksums-of-data.txt
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@@ -1,4 +1,6 @@
# Generated by script/print-nia-checksums.sh
OK. 9720c028 test/data/36.png
OK. f2a0a3f6 test/data/49.png
OK. d3bb0beb test/data/DCI-P3-D65.icc
OK. 646e081a test/data/animated-red-blue.000000.nie
OK. 181c6916 test/data/animated-red-blue.000001.nie