Added full clay border support to draw (#28)

Co-authored-by: Zachary Levy <zachary@sunforge.is>
Reviewed-on: #28

draw/draw_qr/draw_qr.odin

@@ -1,54 +1,71 @@
 package draw_qr
 
+import "core:mem"
+import "core:slice"
+
 import draw ".."
 import "../../qrcode"
 
 DFT_QR_DARK :: draw.BLACK // Default QR code dark module color.
 DFT_QR_LIGHT :: draw.WHITE // Default QR code light module color.
 DFT_QR_BOOST_ECL :: true // Default QR error correction level boost.
+DFT_QR_QUIET_ZONE :: 4 // Default light-pixel border on each side; 4 is the QR spec value.
 
-// Returns the number of bytes to_texture will write for the given encoded
-// QR buffer. Equivalent to size*size*4 where size = qrcode.get_size(qrcode_buf).
-texture_size :: #force_inline proc(qrcode_buf: []u8) -> int {
+// Returns the number of bytes to_texture will write. Equals dim*dim*4 where
+// dim = qrcode.get_size(qrcode_buf) + 2*quiet_zone.
+texture_size :: #force_inline proc(qrcode_buf: []u8, quiet_zone: int = DFT_QR_QUIET_ZONE) -> int {
 	size := qrcode.get_size(qrcode_buf)
-	return size * size * 4
+	if size == 0 || quiet_zone < 0 do return 0
+	padded_size := size + 2 * quiet_zone
+	return padded_size * padded_size * 4
 }
 
 // Decodes an encoded QR buffer into tightly-packed RGBA pixel data written to
 // texture_buf. No allocations, no GPU calls. Returns the Texture_Desc the
 // caller should pass to draw.register_texture alongside texture_buf.
 //
+// quiet_zone adds that many `light` pixels on each side; the spec value is 4.
+// Final dimension is qrcode.get_size + 2*quiet_zone on each axis.
+//
 // Returns ok=false when:
 //   - qrcode_buf is invalid (qrcode.get_size returns 0).
-//   - texture_buf is smaller than texture_size(qrcode_buf).
+//   - quiet_zone is negative.
+//   - texture_buf is smaller than texture_size(qrcode_buf, quiet_zone).
 @(require_results)
 to_texture :: proc(
 	qrcode_buf: []u8,
 	texture_buf: []u8,
 	dark: draw.Color = DFT_QR_DARK,
 	light: draw.Color = DFT_QR_LIGHT,
+	quiet_zone: int = DFT_QR_QUIET_ZONE,
 ) -> (
 	desc: draw.Texture_Desc,
 	ok: bool,
 ) {
 	size := qrcode.get_size(qrcode_buf)
-	if size == 0 do return {}, false
-	if len(texture_buf) < size * size * 4 do return {}, false
+	if size == 0 || quiet_zone < 0 do return
+	padded_size := size + 2 * quiet_zone
+	if len(texture_buf) < padded_size * padded_size * 4 do return
 
+	// Type-pun to []Color so each store is a single 32-bit write.
+	pixels := mem.slice_data_cast([]draw.Color, texture_buf[:padded_size * padded_size * 4])
+
+	// Bulk-fill with light: handles the border and every light QR module at once.
+	slice.fill(pixels, light)
+
+	// Overwrite only the dark modules, offset by the quiet-zone border.
 	for y in 0 ..< size {
+		row := (y + quiet_zone) * padded_size + quiet_zone
 		for x in 0 ..< size {
-			i := (y * size + x) * 4
-			c := dark if qrcode.get_module(qrcode_buf, x, y) else light
-			texture_buf[i + 0] = c[0]
-			texture_buf[i + 1] = c[1]
-			texture_buf[i + 2] = c[2]
-			texture_buf[i + 3] = c[3]
+			if qrcode.get_module(qrcode_buf, x, y) {
+				pixels[row + x] = dark
+			}
 		}
 	}
 
 	return draw.Texture_Desc {
-			width = u32(size),
-			height = u32(size),
+			width = u32(padded_size),
+			height = u32(padded_size),
 			depth_or_layers = 1,
 			type = .D2,
 			format = .R8G8B8A8_UNORM,
@@ -71,19 +88,20 @@ register_texture_from_raw :: proc(
 	qrcode_buf: []u8,
 	dark: draw.Color = DFT_QR_DARK,
 	light: draw.Color = DFT_QR_LIGHT,
+	quiet_zone: int = DFT_QR_QUIET_ZONE,
 	temp_allocator := context.temp_allocator,
 ) -> (
 	texture: draw.Texture_Id,
 	ok: bool,
 ) {
-	tex_size := texture_size(qrcode_buf)
+	tex_size := texture_size(qrcode_buf, quiet_zone)
 	if tex_size == 0 do return draw.INVALID_TEXTURE, false
 
 	pixels, alloc_err := make([]u8, tex_size, temp_allocator)
 	if alloc_err != nil do return draw.INVALID_TEXTURE, false
 	defer delete(pixels, temp_allocator)
 
-	desc := to_texture(qrcode_buf, pixels, dark, light) or_return
+	desc := to_texture(qrcode_buf, pixels, dark, light, quiet_zone) or_return
 	return draw.register_texture(desc, pixels)
 }
 
@@ -103,6 +121,7 @@ register_texture_from_text :: proc(
 	boost_ecl: bool = DFT_QR_BOOST_ECL,
 	dark: draw.Color = DFT_QR_DARK,
 	light: draw.Color = DFT_QR_LIGHT,
+	quiet_zone: int = DFT_QR_QUIET_ZONE,
 	temp_allocator := context.temp_allocator,
 ) -> (
 	texture: draw.Texture_Id,
@@ -123,7 +142,7 @@ register_texture_from_text :: proc(
 		temp_allocator,
 	) or_return
 
-	return register_texture_from_raw(qrcode_buf, dark, light, temp_allocator)
+	return register_texture_from_raw(qrcode_buf, dark, light, quiet_zone, temp_allocator)
 }
 
 // Encodes arbitrary binary data as a QR Code and registers the result as an RGBA texture.
@@ -142,6 +161,7 @@ register_texture_from_binary :: proc(
 	boost_ecl: bool = DFT_QR_BOOST_ECL,
 	dark: draw.Color = DFT_QR_DARK,
 	light: draw.Color = DFT_QR_LIGHT,
+	quiet_zone: int = DFT_QR_QUIET_ZONE,
 	temp_allocator := context.temp_allocator,
 ) -> (
 	texture: draw.Texture_Id,
@@ -162,18 +182,10 @@ register_texture_from_binary :: proc(
 		temp_allocator,
 	) or_return
 
-	return register_texture_from_raw(qrcode_buf, dark, light, temp_allocator)
+	return register_texture_from_raw(qrcode_buf, dark, light, quiet_zone, temp_allocator)
 }
 
 register_texture_from :: proc {
 	register_texture_from_text,
 	register_texture_from_binary,
 }
-
-// Default fit=.Fit preserves the QR's square aspect; override as needed.
-clay_image :: #force_inline proc(
-	texture: draw.Texture_Id,
-	tint: draw.Color = draw.DFT_TINT,
-) -> draw.Clay_Image_Data {
-	return draw.clay_image_data(texture, fit = .Fit, tint = tint)
-}