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Add advanced color and subsampling options #8

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63d8c60
Add advanced AVIF conversion options: chroma subsampling and bit depth
cursoragent Aug 13, 2025
c94a6ca
Remove redundant HEIC-specific image conversion options
cursoragent Aug 13, 2025
28ba96c
Improve image conversion with ICC profile handling and resize techniques
cursoragent Aug 13, 2025
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4 changes: 4 additions & 0 deletions avif-local-support.php
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Original file line number Diff line number Diff line change
Expand Up @@ -61,6 +61,8 @@ function avif_local_support_activate(): void
add_option('avif_local_support_preserve_color_profile', true);
add_option('avif_local_support_wordpress_logic', true);
add_option('avif_local_support_cache_duration', 3600);
add_option('avif_local_support_chroma_subsampling', '4:2:0');
add_option('avif_local_support_bit_depth', 8);
}

function avif_local_support_deactivate(): void
Expand Down Expand Up @@ -99,6 +101,8 @@ function avif_local_support_uninstall(): void
'avif_local_support_preserve_color_profile',
'avif_local_support_wordpress_logic',
'avif_local_support_cache_duration',
'avif_local_support_chroma_subsampling',
'avif_local_support_bit_depth',
];

foreach ($options as $option) {
Expand Down
71 changes: 71 additions & 0 deletions includes/class-avif-suite.php
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Original file line number Diff line number Diff line change
Expand Up @@ -270,6 +270,63 @@ function (): void {
'avif_local_support_conversion',
[ 'label_for' => 'avif_local_support_wordpress_logic' ]
);

// Advanced options section
register_setting('avif_local_support_settings', 'avif_local_support_chroma_subsampling', [
'type' => 'string',
'default' => '4:2:0',
'sanitize_callback' => [$this, 'sanitize_chroma_subsampling'],
'show_in_rest' => true,
]);
register_setting('avif_local_support_settings', 'avif_local_support_bit_depth', [
'type' => 'integer',
'default' => 8,
'sanitize_callback' => [$this, 'sanitize_bit_depth'],
'show_in_rest' => true,
]);

add_settings_section(
'avif_local_support_advanced',
'',
function (): void {},
'avif-local-support'
);

add_settings_field(
'avif_local_support_chroma_subsampling',
__('Chroma subsampling', 'avif-local-support'),
function (): void {
$value = (string) get_option('avif_local_support_chroma_subsampling', '4:2:0');
$options = ['4:2:0', '4:2:2', '4:4:4'];
echo '<select id="avif_local_support_chroma_subsampling" name="avif_local_support_chroma_subsampling">';
foreach ($options as $opt) {
echo '<option value="' . esc_attr($opt) . '" ' . selected($opt, $value, false) . '>' . esc_html($opt) . '</option>';
}
echo '</select>';
echo '<p class="description">' . esc_html__('Lower subsampling reduces file size; 4:4:4 preserves the most color detail (best for graphics/text).', 'avif-local-support') . '</p>';
},
'avif-local-support',
'avif_local_support_advanced',
[ 'label_for' => 'avif_local_support_chroma_subsampling' ]
);

add_settings_field(
'avif_local_support_bit_depth',
__('Bit depth', 'avif-local-support'),
function (): void {
$value = (int) get_option('avif_local_support_bit_depth', 8);
$options = [8, 10, 12];
echo '<select id="avif_local_support_bit_depth" name="avif_local_support_bit_depth">';
foreach ($options as $opt) {
echo '<option value="' . esc_attr((string) $opt) . '" ' . selected($opt, $value, false) . '>' . esc_html((string) $opt) . '</option>';
}
echo '</select>';
echo '<p class="description">' . esc_html__('Higher bit depths can reduce banding and improve gradients (requires Imagick with AVIF support).', 'avif-local-support') . '</p>';
},
'avif-local-support',
'avif_local_support_advanced',
[ 'label_for' => 'avif_local_support_bit_depth' ]
);
}

public function sanitize_schedule_time(string $value): string
Expand All @@ -285,6 +342,20 @@ public function sanitize_speed($value): int
return $n;
}

public function sanitize_chroma_subsampling($value): string
{
$val = is_string($value) ? $value : '';
$allowed = ['4:2:0', '4:2:2', '4:4:4'];
return in_array($val, $allowed, true) ? $val : '4:2:0';
}

public function sanitize_bit_depth($value): int
{
$n = (int) $value;
$allowed = [8, 10, 12];
return in_array($n, $allowed, true) ? $n : 8;
}

public function render_admin_page(): void
{
if (!current_user_can('manage_options')) {
Expand Down
60 changes: 59 additions & 1 deletion includes/class-converter.php
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Original file line number Diff line number Diff line change
Expand Up @@ -136,6 +136,10 @@ private function convertToAvif(string $sourcePath, string $avifPath, ?array $tar
$speedSetting = max(0, min(10, (int) get_option('avif_local_support_speed', 1)));
$preserveMeta = (bool) get_option('avif_local_support_preserve_metadata', true);
$preserveICC = (bool) get_option('avif_local_support_preserve_color_profile', true);
$chromaSubsampling = (string) get_option('avif_local_support_chroma_subsampling', '4:2:0');
if (!in_array($chromaSubsampling, ['4:2:0','4:2:2','4:4:4'], true)) { $chromaSubsampling = '4:2:0'; }
$bitDepthSetting = (int) get_option('avif_local_support_bit_depth', 8);
if (!in_array($bitDepthSetting, [8,10,12], true)) { $bitDepthSetting = 8; }

// Ensure directory exists
$dir = \dirname($avifPath);
Expand All @@ -156,6 +160,10 @@ private function convertToAvif(string $sourcePath, string $avifPath, ?array $tar
}
}

// Detect whether source has an embedded ICC profile
$hasIcc = false;
try { $maybeIcc = $im->getImageProfile('icc'); $hasIcc = !empty($maybeIcc); } catch (\Throwable $e) {}

if ($targetDimensions && isset($targetDimensions['width'], $targetDimensions['height'])) {
$srcW = $im->getImageWidth();
$srcH = $im->getImageHeight();
Expand All @@ -175,19 +183,47 @@ private function convertToAvif(string $sourcePath, string $avifPath, ?array $tar
$cropY = (int) (($srcH - $cropH) / 2);
}
$im->cropImage($cropW, $cropH, $cropX, $cropY);

// Tweak Lanczos filter and use linear-light resize for untagged images
try { $im->setOption('filter:blur', '0.985'); } catch (\Throwable $e) {}
try { $im->setOption('filter:window', 'Jinc'); } catch (\Throwable $e) {}
try { $im->setOption('filter:lobes', '3'); } catch (\Throwable $e) {}
if (!$hasIcc) {
try { $im->transformImageColorspace(\Imagick::COLORSPACE_RGB); } catch (\Throwable $e) {}
}
$im->resizeImage($tW, $tH, \Imagick::FILTER_LANCZOS, 1.0);
if (!$hasIcc) {
try { $im->transformImageColorspace(\Imagick::COLORSPACE_SRGB); } catch (\Throwable $e) {}
}
// Mild post-resize sharpening to restore micro-contrast
try { $im->unsharpMaskImage(0.0, 0.8, 0.9, 0.02); } catch (\Throwable $e) {}
}

$im->setImageFormat('AVIF');
$im->setImageCompressionQuality($quality);
$im->setOption('avif:speed', (string) min(8, $speedSetting));
// Advanced: chroma subsampling and bit depth
$im->setOption('avif:chroma-subsampling', $chromaSubsampling);
$im->setOption('avif:depth', (string) $bitDepthSetting);
try { $im->setImageDepth($bitDepthSetting); } catch (\Throwable $e) {}

if ($preserveMeta || $preserveICC) {
try {
$src = new \Imagick($sourcePath);
if ($preserveICC) {
$icc = $src->getImageProfile('icc');
if (!empty($icc)) { $im->setImageProfile('icc', $icc); }
if (!empty($icc)) {
$im->setImageProfile('icc', $icc);
} else {
// Assign sRGB only (do not transform) when no ICC exists
$srgbPath = $this->findSrgbProfile();
if ($srgbPath && is_readable($srgbPath)) {
$srgbBytes = @file_get_contents($srgbPath);
if ($srgbBytes !== false && $srgbBytes !== '') {
$im->setImageProfile('icc', $srgbBytes);
}
}
}
}
if ($preserveMeta) {
foreach (['exif', 'xmp', 'iptc'] as $profile) {
Expand Down Expand Up @@ -482,4 +518,26 @@ public function convertAttachmentNow(int $attachmentId): array

return $results;
}

/**
* Try to locate a system sRGB ICC profile to tag unprofiled images without converting pixels.
*/
private function findSrgbProfile(): ?string
{
$candidates = [
'/usr/share/color/icc/sRGB.icc',
'/usr/share/color/icc/colord/sRGB.icc',
'/usr/share/color/icc/ghostscript/sRGB.icc',
'/usr/local/share/color/icc/sRGB.icc',
'/usr/share/icc/sRGB.icc',
'C:\\Windows\\System32\\spool\\drivers\\color\\sRGB Color Space Profile.icm',
'/System/Library/ColorSync/Profiles/sRGB Profile.icc',
];
foreach ($candidates as $path) {
if (@is_file($path) && @is_readable($path)) {
return $path;
}
}
return null;
}
}