improve gflags argument handling (#421)

* improve gflags argument handling

* fix lint failure

* oops!

* add a compat method

* throw an error for bad flag

* another lint

Author: jcupitt

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## master
 
 * improve NULL pointer handling [dloebl]
+* improve GFlags argument handling [jcupitt]
 
 ## Version 2.2.4 (2025-06-05)
 

lib/vips/gvalue.rb

@@ -25,7 +25,7 @@ class GValue < FFI::ManagedStruct
       :data, [:ulong_long, 2]
 
     # convert an enum value (str/symb/int) into an int ready for libvips
-    def self.from_nick(gtype, value)
+    def self.enum_from_nick(gtype, value)
       value = value.to_s if value.is_a? Symbol
 
       if value.is_a? String
@@ -40,6 +40,43 @@ def self.from_nick(gtype, value)
       value
     end
 
+    # compatibility ... we used to call it this, perhaps someone has used this
+    # internal method
+    def self.from_nick(gtype, value)
+      GValue.enum_from_nick(gtype, value)
+    end
+
+    # convert an flags value (array[str/symb/int] | str/symb/int) into an
+    # int ready for libvips
+    def self.flags_from_nick(gtype, value)
+      if value.is_a? String
+        # libvips will parse strings like "sub|up" etc.
+        name = value.tr("_", "-")
+        value = Vips.vips_flags_from_nick "ruby-vips", gtype, name
+      else
+        value = [value] if !value.is_a? Array
+
+        # convert each item to a set of bits, OR them together
+        result = 0
+        value.map do |item|
+          item = item.to_s if item.is_a? Symbol
+          if item.is_a? String
+            name = item.tr("_", "-")
+            item = Vips.vips_flags_from_nick "ruby-vips", gtype, name
+            if item == -1
+              raise Vips::Error
+            end
+          end
+
+          result |= item
+        end
+
+        value = result
+      end
+
+      value
+    end
+
     # convert an int enum back into a symbol
     def self.to_nick(gtype, enum_value)
       enum_name = Vips.vips_enum_nick gtype, enum_value
@@ -148,10 +185,11 @@ def set value
       else
         case fundamental
         when GFLAGS_TYPE
-          ::GObject.g_value_set_flags self, value
+          flags_value = GValue.flags_from_nick(self[:gtype], value)
+          ::GObject.g_value_set_flags self, flags_value
 
         when GENUM_TYPE
-          enum_value = GValue.from_nick(self[:gtype], value)
+          enum_value = GValue.enum_from_nick(self[:gtype], value)
           ::GObject.g_value_set_enum self, enum_value
 
         when GOBJECT_TYPE

lib/vips/image.rb

@@ -114,12 +114,12 @@ def self.smap x, &block
     end
 
     def self.complex? format
-      format_number = GObject::GValue.from_nick BAND_FORMAT_TYPE, format
+      format_number = GObject::GValue.enum_from_nick BAND_FORMAT_TYPE, format
       Vips.vips_band_format_iscomplex(format_number) != 0
     end
 
     def self.float? format
-      format_number = GObject::GValue.from_nick BAND_FORMAT_TYPE, format
+      format_number = GObject::GValue.enum_from_nick BAND_FORMAT_TYPE, format
       Vips.vips_band_format_isfloat(format_number) != 0
     end
 
@@ -380,7 +380,7 @@ def self.new_from_memory data, width, height, bands, format
         size = data.bytesize
       end
 
-      format_number = GObject::GValue.from_nick BAND_FORMAT_TYPE, format
+      format_number = GObject::GValue.enum_from_nick BAND_FORMAT_TYPE, format
       vi = Vips.vips_image_new_from_memory data, size,
         width, height, bands, format_number
       raise Vips::Error if vi.null?
@@ -405,7 +405,7 @@ def self.new_from_memory data, width, height, bands, format
     # @param format [Symbol] band format
     # @return [Image] the loaded image
     def self.new_from_memory_copy data, width, height, bands, format
-      format_number = GObject::GValue.from_nick BAND_FORMAT_TYPE, format
+      format_number = GObject::GValue.enum_from_nick BAND_FORMAT_TYPE, format
 
       if data.is_a?(FFI::Pointer)
         if data.size == UNKNOWN_POINTER_SIZE
@@ -1319,7 +1319,7 @@ def composite overlay, mode, **opts
       end
 
       mode = mode.map do |x|
-        GObject::GValue.from_nick Vips::BLEND_MODE_TYPE, x
+        GObject::GValue.enum_from_nick Vips::BLEND_MODE_TYPE, x
       end
 
       Vips::Image.composite([self] + overlay, mode, **opts)

lib/vips/object.rb

@@ -125,6 +125,7 @@ class Progress < FFI::Struct
 
   attach_function :vips_enum_from_nick, [:string, :GType, :string], :int
   attach_function :vips_enum_nick, [:GType, :int], :string
+  attach_function :vips_flags_from_nick, [:string, :GType, :string], :int
 
   attach_function :vips_value_set_ref_string,
     [GObject::GValue.ptr, :string], :void

spec/vips_spec.rb

@@ -166,6 +166,35 @@
       expect(rot.bands).to eq(1)
     end
 
+    it "can handle symbol flag arguments" do
+      black = Vips::Operation.call "black", [200, 200]
+      bytes = Vips::Operation.call "pngsave_buffer", [black], keep: :icc
+
+      expect(bytes.length).to be > 100
+    end
+
+    it "can handle int flag arguments" do
+      black = Vips::Operation.call "black", [200, 200]
+      bytes = Vips::Operation.call "pngsave_buffer", [black], keep: 1 << 3
+
+      expect(bytes.length).to be > 100
+    end
+
+    it "can handle string flag arguments" do
+      black = Vips::Operation.call "black", [200, 200]
+      bytes = Vips::Operation.call "pngsave_buffer", [black], keep: "icc"
+
+      expect(bytes.length).to be > 100
+    end
+
+    it "can handle array flag arguments" do
+      black = Vips::Operation.call "black", [200, 200]
+      bytes = Vips::Operation.call "pngsave_buffer", [black],
+        keep: [:icc, :xmp]
+
+      expect(bytes.length).to be > 100
+    end
+
     it "can return optional output args" do
       point = Vips::Operation.call "black", [1, 1]
       test = Vips::Operation.call "embed", [point, 20, 10, 100, 100],