diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/card.lua | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/lib/card.lua b/lib/card.lua index 320d3af..474228d 100644 --- a/lib/card.lua +++ b/lib/card.lua @@ -30,10 +30,23 @@ function M.text(cr, x, y, s) end -- Measured width and height of a string under the current font. +-- One reused extents struct for every measurement, allocated at load. +-- +-- Not per call: cairo_text_extents_t:create() leaks. 5000 allocations grow +-- Lua's heap by ~182KB that collectgarbage() never reclaims, and calling +-- :destroy() on each one does NOT help (measured: same 182KB either way). +-- Reusing a single struct costs 0KB. In a draw hook running every 2s with +-- several measured strings per frame, the per-call version bleeds memory for as +-- long as conky is up, which is exactly the kind of fault a screenshot cannot +-- show. +-- +-- Safe because the draw hook is single-threaded and each measure() consumes the +-- values before the next call overwrites them. +local extents = cairo_text_extents_t:create() + function M.measure(cr, s) - local e = cairo_text_extents_t:create() - cairo_text_extents(cr, s, e) - return e.width, e.height + cairo_text_extents(cr, s, extents) + return extents.width, extents.height end -- Right-aligned text: x is the RIGHT edge. |