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Purge cached text sprites before releasing a font #441

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Open
Purge cached text sprites before releasing a font#441

Description

@botoddly
botoddly
opened on Aug 27, 2026

Problem

FontSystem.ReleaseFont closes the native TTF_Font and frees its native data, but cached text sprites keyed by that Font remain in the text sprite cache. The cache key keeps the released Font object reachable.

If a cached entry later becomes unreachable and is removed, requesting the same text and released Font again misses the cache and RenderTextToSurface calls SDL_ttf with the closed native font pointer. This makes the public Font.Dispose path capable of reaching a use-after-release native handle.

Scope

  • Remove every cached text-sprite entry keyed by a Font before closing that font.
  • Invalidate any surviving borrowed texture handles before releasing their backing textures.
  • Ensure subsequent text creation with a released Font fails predictably before entering SDL_ttf.
  • Keep disposal idempotent.

Tests

  • Releasing one font removes only text sprites belonging to that font.
  • Cached sprites belonging to other fonts remain valid.
  • A retained text asset for the released font is invalidated before its backing texture is released.
  • Creating or measuring text with a released font throws ObjectDisposedException without calling SDL_ttf.
  • Releasing the same font more than once is safe.

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      , 'i'); if (__m === '*' || __re.test(location.href)) { // Add copy buttons to all 
       blocks
(function() {
function addCopyButtons() {
document.querySelectorAll('pre code').forEach(function(codeBlock) {
if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;
codeBlock.parentElement.setAttribute('data-copy-added', 'true');
var btn = document.createElement('button');
btn.textContent = 'Copy';
btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';
btn.onmouseover = function() { this.style.opacity = '1'; };
btn.onmouseout = function() { this.style.opacity = '0.7'; };
btn.onclick = function() {
navigator.clipboard.writeText(codeBlock.textContent).then(function() {
btn.textContent = 'Copied!';
setTimeout(function() { btn.textContent = 'Copy'; }, 1500);
});
};
codeBlock.parentElement.style.position = 'relative';
codeBlock.parentElement.appendChild(btn);
});
}
addCopyButtons();
// Re-run on dynamic content
var observer = new MutationObserver(addCopyButtons);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '
Purge cached text sprites before releasing a font · Issue #441 · stanoddly/Pixely · GitHub
      Skip to content
      Purge cached text sprites before releasing a font #441
      Open
      Open
      Purge cached text sprites before releasing a font#441
      Description
      @botoddly
      botoddly
      opened on Aug 27, 2026
      Problem
      FontSystem.ReleaseFont closes the native TTF_Font and frees its native data, but cached text sprites keyed by that Font remain in the text sprite cache. The cache key keeps the released Font object reachable.
      If a cached entry later becomes unreachable and is removed, requesting the same text and released Font again misses the cache and RenderTextToSurface calls SDL_ttf with the closed native font pointer. This makes the public Font.Dispose path capable of reaching a use-after-release native handle.
      Scope
      • Remove every cached text-sprite entry keyed by a Font before closing that font.
      • Invalidate any surviving borrowed texture handles before releasing their backing textures.
      • Ensure subsequent text creation with a released Font fails predictably before entering SDL_ttf.
      • Keep disposal idempotent.
      Tests
      • Releasing one font removes only text sprites belonging to that font.
      • Cached sprites belonging to other fonts remain valid.
      • A retained text asset for the released font is invalidated before its backing texture is released.
      • Creating or measuring text with a released font throws ObjectDisposedException without calling SDL_ttf.
      • Releasing the same font more than once is safe.
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, 'i');
if (__m === '*' || __re.test(location.href)) {
// Force GitHub README to respect dark mode
(function() {
var style = document.createElement('style');
style.textContent = '
.markdown-body {
color-scheme: dark light;
}
.markdown-body pre { background: #161b22 !important; }
.markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }
.markdown-body table th, .markdown-body table td { border-color: #30363d !important; }
.markdown-body img { background: #0d1117; }
.markdown-body blockquote { border-left-color: #8b949e; }
.markdown-body hr { border-color: #30363d; }
';
document.head.appendChild(style);
})();
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
Purge cached text sprites before releasing a font · Issue #441 · stanoddly/Pixely · GitHub
          Skip to content
          Purge cached text sprites before releasing a font #441
          Open
          Open
          Purge cached text sprites before releasing a font#441
          Description
          @botoddly
          botoddly
          opened on Aug 27, 2026
          Problem
          FontSystem.ReleaseFont closes the native TTF_Font and frees its native data, but cached text sprites keyed by that Font remain in the text sprite cache. The cache key keeps the released Font object reachable.
          If a cached entry later becomes unreachable and is removed, requesting the same text and released Font again misses the cache and RenderTextToSurface calls SDL_ttf with the closed native font pointer. This makes the public Font.Dispose path capable of reaching a use-after-release native handle.
          Scope
          • Remove every cached text-sprite entry keyed by a Font before closing that font.
          • Invalidate any surviving borrowed texture handles before releasing their backing textures.
          • Ensure subsequent text creation with a released Font fails predictably before entering SDL_ttf.
          • Keep disposal idempotent.
          Tests
          • Releasing one font removes only text sprites belonging to that font.
          • Cached sprites belonging to other fonts remain valid.
          • A retained text asset for the released font is invalidated before its backing texture is released.
          • Creating or measuring text with a released font throws ObjectDisposedException without calling SDL_ttf.
          • Releasing the same font more than once is safe.
          Metadata
          Metadata
          Assignees
          No one assigned
            Labels
            No labels
            No labels
            Projects
            No projects
              Milestone
              No milestone
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              None yet
              Development
              No branches or pull requests
              Issue actions
              
, 'i');
if (__m === '*' || __re.test(location.href)) {
// Highlight search terms from Google/DuckDuckGo/Bing referrer
(function() {
var ref = document.referrer;
var terms = [];
if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {
var url = new URL(ref);
var q = url.searchParams.get('q') || url.searchParams.get('p');
if (q) {
terms = q.split(/\s+/).filter(function(t) { return t.length > 2; });
}
}
if (terms.length === 0) return;
var style = document.createElement('style');
style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';
document.head.appendChild(style);
function highlight(node) {
if (node.nodeType === 3) { // text node
var text = node.textContent;
var found = false;
terms.forEach(function(term) {
var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\]\\]/g, '\\') + ')', 'gi');
if (regex.test(text)) {
found = true;
var frag = document.createDocumentFragment();
var parts = text.split(regex);
parts.forEach(function(part, i) {
if (i % 2 === 0) {
frag.appendChild(document.createTextNode(part));
} else {
var span = document.createElement('span');
span.className = 'userscript-highlight';
span.textContent = part;
frag.appendChild(span);
}
});
node.parentNode.replaceChild(frag, node);
}
});
} else if (node.nodeType === 1 && node.childNodes) { // element
var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];
if (!skipTags.includes(node.tagName)) {
Array.from(node.childNodes).forEach(highlight);
}
}
}
highlight(document.body);
// Re-highlight on dynamic content
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1 || node.nodeType === 3) highlight(node);
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
Purge cached text sprites before releasing a font · Issue #441 · stanoddly/Pixely · GitHub
              Skip to content
              Purge cached text sprites before releasing a font #441
              Open
              Open
              Purge cached text sprites before releasing a font#441
              Description
              @botoddly
              botoddly
              opened on Aug 27, 2026
              Problem
              FontSystem.ReleaseFont closes the native TTF_Font and frees its native data, but cached text sprites keyed by that Font remain in the text sprite cache. The cache key keeps the released Font object reachable.
              If a cached entry later becomes unreachable and is removed, requesting the same text and released Font again misses the cache and RenderTextToSurface calls SDL_ttf with the closed native font pointer. This makes the public Font.Dispose path capable of reaching a use-after-release native handle.
              Scope
              • Remove every cached text-sprite entry keyed by a Font before closing that font.
              • Invalidate any surviving borrowed texture handles before releasing their backing textures.
              • Ensure subsequent text creation with a released Font fails predictably before entering SDL_ttf.
              • Keep disposal idempotent.
              Tests
              • Releasing one font removes only text sprites belonging to that font.
              • Cached sprites belonging to other fonts remain valid.
              • A retained text asset for the released font is invalidated before its backing texture is released.
              • Creating or measuring text with a released font throws ObjectDisposedException without calling SDL_ttf.
              • Releasing the same font more than once is safe.
              Metadata
              Metadata
              Assignees
              No one assigned
                Labels
                No labels
                No labels
                Projects
                No projects
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                  No milestone
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                  None yet
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                  No branches or pull requests
                  Issue actions
                  
, 'i');
if (__m === '*' || __re.test(location.href)) {
// Strip utm_, fbclid, gclid, etc. from all links on page
(function() {
var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',
'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',
'ref', 'ref_src', 'source', 'medium', 'campaign'];
function cleanUrl(url) {
try {
var u = new URL(url, window.location.origin);
var changed = false;
trackingParams.forEach(function(p) {
if (u.searchParams.has(p)) {
u.searchParams.delete(p);
changed = true;
}
});
return changed ? u.toString() : url;
} catch (e) {
return url;
}
}
function cleanLinks() {
document.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
cleanLinks();
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1) {
if (node.tagName === 'A') cleanLinks();
node.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '
Purge cached text sprites before releasing a font · Issue #441 · stanoddly/Pixely · GitHub
                  Skip to content
                  Purge cached text sprites before releasing a font #441
                  Open
                  Open
                  Purge cached text sprites before releasing a font#441
                  Description
                  @botoddly
                  botoddly
                  opened on Aug 27, 2026
                  Problem
                  FontSystem.ReleaseFont closes the native TTF_Font and frees its native data, but cached text sprites keyed by that Font remain in the text sprite cache. The cache key keeps the released Font object reachable.
                  If a cached entry later becomes unreachable and is removed, requesting the same text and released Font again misses the cache and RenderTextToSurface calls SDL_ttf with the closed native font pointer. This makes the public Font.Dispose path capable of reaching a use-after-release native handle.
                  Scope
                  • Remove every cached text-sprite entry keyed by a Font before closing that font.
                  • Invalidate any surviving borrowed texture handles before releasing their backing textures.
                  • Ensure subsequent text creation with a released Font fails predictably before entering SDL_ttf.
                  • Keep disposal idempotent.
                  Tests
                  • Releasing one font removes only text sprites belonging to that font.
                  • Cached sprites belonging to other fonts remain valid.
                  • A retained text asset for the released font is invalidated before its backing texture is released.
                  • Creating or measuring text with a released font throws ObjectDisposedException without calling SDL_ttf.
                  • Releasing the same font more than once is safe.
                  Metadata
                  Metadata
                  Assignees
                  No one assigned
                    Labels
                    No labels
                    No labels
                    Projects
                    No projects
                      Milestone
                      No milestone
                      Relationships
                      None yet
                      Development
                      No branches or pull requests
                      Issue actions
                      
, 'i');
if (__m === '*' || __re.test(location.href)) {
// Auto-enable theater mode on YouTube
(function() {
function tryTheater() {
var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]');
if (btn && !btn.classList.contains('activated')) {
btn.click();
}
}
// Try immediately
tryTheater();
// Try after navigation (SPA)
var lastUrl = location.href;
setInterval(function() {
if (location.href !== lastUrl) {
lastUrl = location.href;
setTimeout(tryTheater, 500);
}
}, 1000);
// Also try on player load
var observer = new MutationObserver(tryTheater);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
Purge cached text sprites before releasing a font · Issue #441 · stanoddly/Pixely · GitHub
                      Skip to content
                      Purge cached text sprites before releasing a font #441
                      Open
                      Open
                      Purge cached text sprites before releasing a font#441
                      Description
                      @botoddly
                      botoddly
                      opened on Aug 27, 2026
                      Problem
                      FontSystem.ReleaseFont closes the native TTF_Font and frees its native data, but cached text sprites keyed by that Font remain in the text sprite cache. The cache key keeps the released Font object reachable.
                      If a cached entry later becomes unreachable and is removed, requesting the same text and released Font again misses the cache and RenderTextToSurface calls SDL_ttf with the closed native font pointer. This makes the public Font.Dispose path capable of reaching a use-after-release native handle.
                      Scope
                      • Remove every cached text-sprite entry keyed by a Font before closing that font.
                      • Invalidate any surviving borrowed texture handles before releasing their backing textures.
                      • Ensure subsequent text creation with a released Font fails predictably before entering SDL_ttf.
                      • Keep disposal idempotent.
                      Tests
                      • Releasing one font removes only text sprites belonging to that font.
                      • Cached sprites belonging to other fonts remain valid.
                      • A retained text asset for the released font is invalidated before its backing texture is released.
                      • Creating or measuring text with a released font throws ObjectDisposedException without calling SDL_ttf.
                      • Releasing the same font more than once is safe.
                      Metadata
                      Metadata
                      Assignees
                      No one assigned
                        Labels
                        No labels
                        No labels
                        Projects
                        No projects
                          Milestone
                          No milestone
                          Relationships
                          None yet
                          Development
                          No branches or pull requests
                          Issue actions
                          
, 'i');
if (__m === '*' || __re.test(location.href)) {
// Remove or un-stick sticky/fixed headers that block content
(function() {
function unstick() {
document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) {
if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {
el.style.position = 'static';
el.style.top = 'auto';
el.style.zIndex = 'auto';
}
});
}
unstick();
var observer = new MutationObserver(unstick);
observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });
})();
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
Purge cached text sprites before releasing a font · Issue #441 · stanoddly/Pixely · GitHub
                          Skip to content
                          Purge cached text sprites before releasing a font #441
                          Open
                          Open
                          Purge cached text sprites before releasing a font#441
                          Description
                          @botoddly
                          botoddly
                          opened on Aug 27, 2026
                          Problem
                          FontSystem.ReleaseFont closes the native TTF_Font and frees its native data, but cached text sprites keyed by that Font remain in the text sprite cache. The cache key keeps the released Font object reachable.
                          If a cached entry later becomes unreachable and is removed, requesting the same text and released Font again misses the cache and RenderTextToSurface calls SDL_ttf with the closed native font pointer. This makes the public Font.Dispose path capable of reaching a use-after-release native handle.
                          Scope
                          • Remove every cached text-sprite entry keyed by a Font before closing that font.
                          • Invalidate any surviving borrowed texture handles before releasing their backing textures.
                          • Ensure subsequent text creation with a released Font fails predictably before entering SDL_ttf.
                          • Keep disposal idempotent.
                          Tests
                          • Releasing one font removes only text sprites belonging to that font.
                          • Cached sprites belonging to other fonts remain valid.
                          • A retained text asset for the released font is invalidated before its backing texture is released.
                          • Creating or measuring text with a released font throws ObjectDisposedException without calling SDL_ttf.
                          • Releasing the same font more than once is safe.
                          Metadata
                          Metadata
                          Assignees
                          No one assigned
                            Labels
                            No labels
                            No labels
                            Projects
                            No projects
                              Milestone
                              No milestone
                              Relationships
                              None yet
                              Development
                              No branches or pull requests
                              Issue actions
                              
, 'i');
if (__m === '*' || __re.test(location.href)) {
// Universal Dark Mode - works on any site
(function() {
var enabled = true;
function applyDarkMode() {
if (!enabled) return;
// Create style element if it doesn't exist
var style = document.getElementById('universal-dark-mode-style');
if (!style) {
style = document.createElement('style');
style.id = 'universal-dark-mode-style';
document.head.appendChild(style);
}
// Dark mode CSS - inverts colors but preserves images/video
style.textContent = '
/* Invert everything except media */
html {
filter: invert(1) hue-rotate(180deg) !important;
background: #1a1a2e !important;
}
/* Restore images, videos, iframes, canvas */
img, video, iframe, canvas, svg, picture, [style*="background-image"] {
filter: invert(1) hue-rotate(180deg) !important;
}
/* Preserve specific elements that should not be inverted */
.no-dark-mode, .no-dark-mode *,
[data-theme="light"], [data-theme="light"],
.ace_editor, .ace_editor *,
.CodeMirror, .CodeMirror *,
.monaco-editor, .monaco-editor *,
.markdown-body pre, .markdown-body pre *,
.highlight, .highlight *,
pre code, pre code * {
filter: none !important;
}
/* Fix common UI elements */
.modal, .popup, .dropdown-menu, .tooltip, .popover {
filter: invert(1) hue-rotate(180deg) !important;
background: #2d2d44 !important;
border-color: #444 !important;
}
/* Scrollbars */
::-webkit-scrollbar { background: #1a1a2e !important; }
::-webkit-scrollbar-thumb { background: #444 !important; }
::-webkit-scrollbar-thumb:hover { background: #555 !important; }
/* Selection */
::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
';
}
function removeDarkMode() {
var style = document.getElementById('universal-dark-mode-style');
if (style) style.remove();
}
// Toggle with Alt+Shift+D
document.addEventListener('keydown', function(e) {
if (e.altKey && e.shiftKey && e.key === 'D') {
e.preventDefault();
enabled = !enabled;
if (enabled) {
applyDarkMode();
console.log('[Universal Dark Mode] Enabled');
} else {
removeDarkMode();
console.log('[Universal Dark Mode] Disabled');
}
}
});
// Apply on load
applyDarkMode();
// Re-apply on dynamic content
var observer = new MutationObserver(function(mutations) {
if (enabled && !document.getElementById('universal-dark-mode-style')) {
applyDarkMode();
}
});
observer.observe(document.head, { childList: true });
console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');
})();
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();
Purge cached text sprites before releasing a font · Issue #441 · stanoddly/Pixely · GitHub
                              Skip to content
                              Purge cached text sprites before releasing a font #441
                              Open
                              Open
                              Purge cached text sprites before releasing a font#441
                              Description
                              @botoddly
                              botoddly
                              opened on Aug 27, 2026
                              Problem
                              FontSystem.ReleaseFont closes the native TTF_Font and frees its native data, but cached text sprites keyed by that Font remain in the text sprite cache. The cache key keeps the released Font object reachable.
                              If a cached entry later becomes unreachable and is removed, requesting the same text and released Font again misses the cache and RenderTextToSurface calls SDL_ttf with the closed native font pointer. This makes the public Font.Dispose path capable of reaching a use-after-release native handle.
                              Scope
                              • Remove every cached text-sprite entry keyed by a Font before closing that font.
                              • Invalidate any surviving borrowed texture handles before releasing their backing textures.
                              • Ensure subsequent text creation with a released Font fails predictably before entering SDL_ttf.
                              • Keep disposal idempotent.
                              Tests
                              • Releasing one font removes only text sprites belonging to that font.
                              • Cached sprites belonging to other fonts remain valid.
                              • A retained text asset for the released font is invalidated before its backing texture is released.
                              • Creating or measuring text with a released font throws ObjectDisposedException without calling SDL_ttf.
                              • Releasing the same font more than once is safe.
                              Metadata
                              Metadata
                              Assignees
                              No one assigned
                                Labels
                                No labels
                                No labels
                                Projects
                                No projects
                                  Milestone
                                  No milestone
                                  Relationships
                                  None yet
                                  Development
                                  No branches or pull requests
                                  Issue actions