background: Add a way to scale a background gradient.

This is a feature request from the chat. Right now, only deprecated
hacks allow this to be implemented. This is a valid use case and
must be supported for HiDPI use cases.
This commit is contained in:
Emmanuel Lepage Vallee 2022-02-05 15:16:21 -08:00
parent e82de8edb4
commit 5ee926d5f1
1 changed files with 187 additions and 6 deletions

View File

@ -23,6 +23,141 @@ local unpack = unpack or table.unpack -- luacheck: globals unpack (compatibility
local background = { mt = {} }
-- If a background is resized with the mouse, it might create a large
-- number of scaled texture. After the cache grows beyond this number, it
-- is purged.
local MAX_CACHE_SIZE = 10
local global_scaled_pattern_cache = setmetatable({}, {__mode = "k"})
local function clone_stops(input, output)
local err, count = input:get_color_stop_count()
if err ~= "SUCCESS" then return end
for idx = 0, count-1 do
local _, off, r, g, b, a = input:get_color_stop_rgba(idx)
output:add_color_stop_rgba(off, r, g, b, a)
end
end
local function stretch_lineal_gradient(input, width, height)
-- First, get the original values.
local err, x0, y0, x1, y1 = input:get_linear_points()
if err ~= "SUCCESS" then
return input
end
local new_x0, new_y0 = x1 == 0 and 0 or ((x0/x1)*width), y1 == 0 and 0 or ((y0/y1)*height)
local output = cairo.Pattern.create_linear(new_x0, new_y0, width, height)
clone_stops(input, output)
return output
end
local function stretch_radial_gradient(input, width, height)
local err, cx0, cy0, radius0, cx1, cy1, radius1 = input:get_radial_circles()
if err ~= "SUCCESS" then
return input
end
-- Create a box for the original gradient, starting at 0x0.
local x1 = math.max(cx0 + radius0, cx1 + radius1)
local y1 = math.max(cy0 + radius0, cy1 + radius1)
-- Now scale this box to `width`x`height`
local x_factor, y_factor = width/x1, height/y1
local rad_factor = math.sqrt(width^2 + height^2) / math.sqrt(x1^1+y1^2)
local output = cairo.Pattern.create_radial(
cx0*x_factor, cy0*y_factor, radius0*rad_factor, cx1*x_factor, cx1*y_factor, radius1*rad_factor
)
clone_stops(input, output)
return output
end
local function get_pattern_size(pat)
local t = pat.type
if t == "LINEAR" then
local _, _, _, x1, y1 = pat:get_linear_points()
return x1, y1
elseif t == "RADIAL" then
local _, _, _, cx1, cy1, _ = pat:get_radial_circles()
return cx1, cy1
end
end
local function stretch_common(self, width, height)
if (not self._private.background) and (not self._private.bgimage) then return end
if not (self._private.stretch_horizontally or self._private.stretch_vertically) then
return self._private.background, self._private.bgimage
end
local old = self._private.background
local size_w, size_h = get_pattern_size(old)
-- Note that technically, we could handle cairo.SurfacePattern and
-- cairo.RasterSourcePattern. However, this might create some surprising
-- results. For example switching to a different theme which uses tiled
-- pattern would change the "meaning" of this property.
if not size_w then return end
-- Don't try to resize zero-sized patterns. They are used for
-- generic liear gradient means "there is no gradient in this axis"
if self._private.stretch_vertically and size_h ~= 0 then
size_h = height
end
if self._private.stretch_horizontally and size_w ~= 0 then
size_w = width
end
local hash = size_w.."x"..size_h
if self._private.scale_cache[hash] then
return self._private.scale_cache[hash]
end
if global_scaled_pattern_cache[old] and global_scaled_pattern_cache[old][hash] then
-- Don't bother clearing the cache, if the pattern is already cached
-- elsewhere, it will remain in memory anyway.
self._private.scale_cache[hash] = global_scaled_pattern_cache[old][hash]
self._private.scale_cache_size = self._private.scale_cache_size + 1
end
local t, new = old.type
if t == "LINEAR" then
new = stretch_lineal_gradient(old, size_w, size_h)
elseif t == "RADIAL" then
new = stretch_radial_gradient(old, size_w, size_h)
end
global_scaled_pattern_cache[old] = global_scaled_pattern_cache[old] or setmetatable({}, {__mode = "v"})
global_scaled_pattern_cache[old][hash] = new
-- Prevent the memory leak.
if self._private.scale_cache_size > MAX_CACHE_SIZE then
self._private.scale_cache_size = 0
self._private.scale_cache = {}
end
self._private.scale_cache[hash] = new
self._private.scale_cache_size = self._private.scale_cache_size + 1
return new, self._private.bgimage
end
-- The Cairo SVG backend doesn't support surface as patterns correctly.
-- The result is both glitchy and blocky. It is also impossible to introspect.
-- Calling this function replace the normal code path is a "less correct", but
@ -39,9 +174,11 @@ function background._use_fallback_algorithm()
shape(cr, width, height)
if self._private.background then
local bg = stretch_common(self, width, height)
if bg then
cr:save() --Save to avoid messing with the original source
cr:set_source(self._private.background)
cr:set_source(bg)
cr:fill_preserve()
cr:restore()
end
@ -115,15 +252,18 @@ function background:before_draw_children(context, cr, width, height)
cr:push_group_with_content(cairo.Content.COLOR_ALPHA)
end
local bg, bgimage = stretch_common(self, width, height)
-- Draw the background
if self._private.background then
if bg then
cr:save()
cr:set_source(self._private.background)
cr:set_source(bg)
cr:rectangle(0, 0, width, height)
cr:fill()
cr:restore()
end
if self._private.bgimage then
if bgimage then
cr:save()
if type(self._private.bgimage) == "function" then
self._private.bgimage(context, cr, width, height,unpack(self._private.bgimage_args))
@ -253,6 +393,42 @@ function background:set_children(children)
self:set_widget(children[1])
end
--- Stretch the background gradient horizontally.
--
-- This only works for linear or radial gradients. It does nothing
-- for solid colors, `bgimage` or raster patterns.
--
--@DOC_wibox_container_background_stretch_horizontally_EXAMPLE@
--
-- @property stretch_horizontally
-- @tparam[opt=false] boolean stretch_horizontally
-- @propemits true false
-- @see stretch_vertically
-- @see bg
-- @see gears.color
--- Stretch the background gradient vertically.
--
-- This only works for linear or radial gradients. It does nothing
-- for solid colors, `bgimage` or raster patterns.
--
--@DOC_wibox_container_background_stretch_vertically_EXAMPLE@
--
-- @property stretch_vertically
-- @tparam[opt=false] boolean stretch_vertically
-- @propemits true false
-- @see stretch_horizontally
-- @see bg
-- @see gears.color
for _, orientation in ipairs {"horizontally", "vertically"} do
background["set_stretch_"..orientation] = function(self, value)
self._private["stretch_"..orientation] = value
self:emit_signal("widget::redraw_needed")
self:emit_signal("property::stretch_"..orientation, value)
end
end
--- The background color/pattern/gradient to use.
--
--@DOC_wibox_container_background_bg_EXAMPLE@
@ -352,7 +528,8 @@ end
--
-- If the shape is set, the border will also be shaped.
--
-- See `wibox.container.background.shape` for an usage example.
--@DOC_wibox_container_background_border_width_EXAMPLE@
--
-- @property border_width
-- @tparam[opt=0] number border_width
-- @propertyunit pixel
@ -400,6 +577,8 @@ end
--- Set the color for the border.
--
--@DOC_wibox_container_background_border_color_EXAMPLE@
--
-- See `wibox.container.background.shape` for an usage example.
-- @property border_color
-- @tparam color border_color
@ -513,6 +692,8 @@ local function new(widget, bg, shape)
gtable.crush(ret, background, true)
ret._private.shape = shape
ret._private.scale_cache = {}
ret._private.scale_cache_size = 0
ret:set_widget(widget)
ret:set_bg(bg)