Improve speed of loading QOI images

src/PIL/BlpImagePlugin.py

@@ -341,7 +341,7 @@ def _load(self):
             if self._blp_encoding in (4, 5):
                 palette = self._read_palette()
                 data = self._read_bgra(palette)
-                self.set_as_raw(bytes(data))
+                self.set_as_raw(data)
             else:
                 msg = f"Unsupported BLP encoding {repr(self._blp_encoding)}"
                 raise BLPFormatError(msg)
@@ -412,7 +412,7 @@ def _load(self):
             msg = f"Unknown BLP compression {repr(self._blp_compression)}"
             raise BLPFormatError(msg)
 
-        self.set_as_raw(bytes(data))
+        self.set_as_raw(data)
 
 
 class BLPEncoder(ImageFile.PyEncoder):

src/PIL/BmpImagePlugin.py

@@ -291,7 +291,8 @@ def decode(self, buffer):
         rle4 = self.args[1]
         data = bytearray()
         x = 0
-        while len(data) < self.state.xsize * self.state.ysize:
+        dest_length = self.state.xsize * self.state.ysize
+        while len(data) < dest_length:
             pixels = self.fd.read(1)
             byte = self.fd.read(1)
             if not pixels or not byte:

src/PIL/DdsImagePlugin.py

@@ -497,15 +497,16 @@ def decode(self, buffer):
 
         data = bytearray()
         bytecount = bitcount // 8
-        while len(data) < self.state.xsize * self.state.ysize * len(masks):
+        dest_length = self.state.xsize * self.state.ysize * len(masks)
+        while len(data) < dest_length:
             value = int.from_bytes(self.fd.read(bytecount), "little")
             for i, mask in enumerate(masks):
                 masked_value = value & mask
                 # Remove the zero padding, and scale it to 8 bits
                 data += o8(
                     int(((masked_value >> mask_offsets[i]) / mask_totals[i]) * 255)
                 )
-        self.set_as_raw(bytes(data))
+        self.set_as_raw(data)
         return -1, 0
 
 

src/PIL/PpmImagePlugin.py

@@ -307,7 +307,8 @@ def decode(self, buffer: bytes) -> tuple[int, int]:
         out_byte_count = 4 if self.mode == "I" else 1
         out_max = 65535 if self.mode == "I" else 255
         bands = Image.getmodebands(self.mode)
-        while len(data) < self.state.xsize * self.state.ysize * bands * out_byte_count:
+        dest_length = self.state.xsize * self.state.ysize * bands * out_byte_count
+        while len(data) < dest_length:
             pixels = self.fd.read(in_byte_count * bands)
             if len(pixels) < in_byte_count * bands:
                 # eof

src/PIL/QoiImagePlugin.py

@@ -11,7 +11,6 @@
 
 from . import Image, ImageFile
 from ._binary import i32be as i32
-from ._binary import o8
 
 
 def _accept(prefix):
@@ -49,55 +48,61 @@ def _add_to_previous_pixels(self, value):
     def decode(self, buffer):
         self._previously_seen_pixels = {}
         self._previous_pixel = None
-        self._add_to_previous_pixels(b"".join(o8(i) for i in (0, 0, 0, 255)))
+        self._add_to_previous_pixels(bytearray((0, 0, 0, 255)))
 
         data = bytearray()
         bands = Image.getmodebands(self.mode)
-        while len(data) < self.state.xsize * self.state.ysize * bands:
+        dest_length = self.state.xsize * self.state.ysize * bands
+        while len(data) < dest_length:
             byte = self.fd.read(1)[0]
             if byte == 0b11111110:  # QOI_OP_RGB
-                value = self.fd.read(3) + self._previous_pixel[3:]
+                value = bytearray(self.fd.read(3)) + self._previous_pixel[3:]
             elif byte == 0b11111111:  # QOI_OP_RGBA
                 value = self.fd.read(4)
             else:
                 op = byte >> 6
                 if op == 0:  # QOI_OP_INDEX
                     op_index = byte & 0b00111111
-                    value = self._previously_seen_pixels.get(op_index, (0, 0, 0, 0))
+                    value = self._previously_seen_pixels.get(
+                        op_index, bytearray((0, 0, 0, 0))
+                    )
                 elif op == 1:  # QOI_OP_DIFF
-                    value = (
-                        (self._previous_pixel[0] + ((byte & 0b00110000) >> 4) - 2)
-                        % 256,
-                        (self._previous_pixel[1] + ((byte & 0b00001100) >> 2) - 2)
-                        % 256,
-                        (self._previous_pixel[2] + (byte & 0b00000011) - 2) % 256,
+                    value = bytearray(
+                        (
+                            (self._previous_pixel[0] + ((byte & 0b00110000) >> 4) - 2)
+                            % 256,
+                            (self._previous_pixel[1] + ((byte & 0b00001100) >> 2) - 2)
+                            % 256,
+                            (self._previous_pixel[2] + (byte & 0b00000011) - 2) % 256,
+                            self._previous_pixel[3],
+                        )
                     )
-                    value += (self._previous_pixel[3],)
                 elif op == 2:  # QOI_OP_LUMA
                     second_byte = self.fd.read(1)[0]
                     diff_green = (byte & 0b00111111) - 32
                     diff_red = ((second_byte & 0b11110000) >> 4) - 8
                     diff_blue = (second_byte & 0b00001111) - 8
 
-                    value = tuple(
-                        (self._previous_pixel[i] + diff_green + diff) % 256
-                        for i, diff in enumerate((diff_red, 0, diff_blue))
+                    value = bytearray(
+                        tuple(
+                            (self._previous_pixel[i] + diff_green + diff) % 256
+                            for i, diff in enumerate((diff_red, 0, diff_blue))
+                        )
                     )
-                    value += (self._previous_pixel[3],)
+                    value += self._previous_pixel[3:]
                 elif op == 3:  # QOI_OP_RUN
                     run_length = (byte & 0b00111111) + 1
                     value = self._previous_pixel
                     if bands == 3:
                         value = value[:3]
                     data += value * run_length
                     continue
-                value = b"".join(o8(i) for i in value)
             self._add_to_previous_pixels(value)
 
             if bands == 3:
                 value = value[:3]
             data += value
-        self.set_as_raw(bytes(data))
+        self.set_as_raw(data)
         return -1, 0