One image request type instead of five (closes #307)

The new package internal/imagerequest holds the request type, its two
parts Source and Transform, the Format and Fit types, the dimension and
fit checks, the /v1/image/ path parsing and the variant key; it imports
no other package of pixa. imgcache.ParsedURL, imgcache.ImageRequest,
signature.Request, imageprocessor.Request, the second Size, format and
fit types and the conversions between them are gone. The image
processor takes a Transform only. encurl keeps a private struct with the
token's short CBOR field names. VariantKey moves with the function that
makes it. Tests follow the moved and renamed code; the tests of the
removed conversions go with them.

Model: opus-5-5

internal/imageprocessor/avif_too_large_internal_test.go

@@ -6,6 +6,8 @@ import (
 	"errors"
 	"os"
 	"testing"
+
+	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 
 // TestImageProcessor_RefusesAVIFAboveMaxPixels verifies that an AVIF output
@@ -37,22 +39,30 @@ func TestImageProcessor_RefusesAVIFAboveMaxPixels(t *testing.T) {
 	tests := []struct {
 		name          string
 		input         []byte
-		format        Format
+		format        imagerequest.Format
 		width, height int
-		fit           FitMode
+		fit           imagerequest.Fit
 		refused       bool
 	}{
-		{"AVIF at the limit", cutOff, FormatAVIF, 4096, 4096, FitCover, false},
-		{"AVIF above the limit", cutOff, FormatAVIF, 4096, 4097, FitCover, true},
-		{"WebP above the AVIF limit", cutOff, FormatWebP, 4096, 4097, FitCover, false},
+		{"AVIF at the limit", cutOff, imagerequest.FormatAVIF,
+			4096, 4096, imagerequest.FitCover, false},
+		{"AVIF above the limit", cutOff, imagerequest.FormatAVIF,
+			4096, 4097, imagerequest.FitCover, true},
+		{"WebP above the AVIF limit", cutOff, imagerequest.FormatWebP,
+			4096, 4097, imagerequest.FitCover, false},
 		// FitInside does not enlarge, so the output stays 64x32
-		{"AVIF inside a larger size", cutOff, FormatAVIF, 8192, 8192, FitInside, false},
+		{"AVIF inside a larger size", cutOff, imagerequest.FormatAVIF,
+			8192, 8192, imagerequest.FitInside, false},
 		// FitOutside scales 64x32 by 128 to cover 8192x1: 8192x4096
-		{"AVIF outside a smaller size", cutOff, FormatAVIF, 8192, 1, FitOutside, true},
+		{"AVIF outside a smaller size", cutOff, imagerequest.FormatAVIF,
+			8192, 1, imagerequest.FitOutside, true},
 		// With no size, the output keeps the source's 4097x4096
-		{"AVIF of the source's size", largeAVIF, FormatAVIF, 0, 0, FitCover, true},
-		{"orig of an AVIF source", largeAVIF, FormatOriginal, 0, 0, FitCover, true},
-		{"JPEG of the source's size", largeAVIF, FormatJPEG, 0, 0, FitCover, false},
+		{"AVIF of the source's size", largeAVIF, imagerequest.FormatAVIF,
+			0, 0, imagerequest.FitCover, true},
+		{"orig of an AVIF source", largeAVIF, imagerequest.FormatOriginal,
+			0, 0, imagerequest.FitCover, true},
+		{"JPEG of the source's size", largeAVIF, imagerequest.FormatJPEG,
+			0, 0, imagerequest.FitCover, false},
 	}
 
 	for _, tt := range tests {
@@ -60,8 +70,8 @@ func TestImageProcessor_RefusesAVIFAboveMaxPixels(t *testing.T) {
 			t.Parallel()
 
 			_, err := New(Params{}).Process(t.Context(), bytes.NewReader(tt.input),
-				&Request{
-					Size:    Size{Width: tt.width, Height: tt.height},
+				&imagerequest.Transform{
+					Size:    imagerequest.Size{Width: tt.width, Height: tt.height},
 					Format:  tt.format,
 					FitMode: tt.fit,
 				})