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 CBOR field names, so tokens made before still decode. 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/fit_outside_internal_test.go

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"errors"
 	"testing"
+
+	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 
 // TestImageProcessor_RefusesFitOutsideAboveMaximum verifies that FitOutside,
@@ -17,15 +19,20 @@ func TestImageProcessor_RefusesFitOutsideAboveMaximum(t *testing.T) {
 	tests := []struct {
 		name                    string
 		inputWidth, inputHeight int
-		size                    Size
+		size                    imagerequest.Size
 		// wantWidth and wantHeight are the output's, 0 for a refusal
 		wantWidth, wantHeight int
 	}{
-		{"width above the maximum", 3000, 600, Size{Width: 1, Height: 8192}, 0, 0},
-		{"height above the maximum", 600, 3000, Size{Width: 8192, Height: 1}, 0, 0},
-		{"width at the maximum", 1024, 256, Size{Width: 1, Height: 2048}, 8192, 2048},
-		{"height at the maximum", 256, 1024, Size{Width: 2048, Height: 1}, 2048, 8192},
-		{"within the maximum", 3000, 600, Size{Width: 1, Height: 1200}, 6000, 1200},
+		{"width above the maximum", 3000, 600,
+			imagerequest.Size{Width: 1, Height: 8192}, 0, 0},
+		{"height above the maximum", 600, 3000,
+			imagerequest.Size{Width: 8192, Height: 1}, 0, 0},
+		{"width at the maximum", 1024, 256,
+			imagerequest.Size{Width: 1, Height: 2048}, 8192, 2048},
+		{"height at the maximum", 256, 1024,
+			imagerequest.Size{Width: 2048, Height: 1}, 2048, 8192},
+		{"within the maximum", 3000, 600,
+			imagerequest.Size{Width: 1, Height: 1200}, 6000, 1200},
 	}
 
 	for _, tt := range tests {
@@ -36,7 +43,11 @@ func TestImageProcessor_RefusesFitOutsideAboveMaximum(t *testing.T) {
 
 			result, err := New(Params{}).Process(t.Context(),
 				bytes.NewReader(input),
-				&Request{Size: tt.size, Format: FormatJPEG, FitMode: FitOutside})
+				&imagerequest.Transform{
+					Size:    tt.size,
+					Format:  imagerequest.FormatJPEG,
+					FitMode: imagerequest.FitOutside,
+				})
 			if result != nil {
 				t.Logf("Process() made %dx%d", result.Width, result.Height)
 			}
@@ -71,11 +82,11 @@ func TestImageProcessor_FitOutsideSideIsAtLeastOne(t *testing.T) {
 	tests := []struct {
 		name                    string
 		inputWidth, inputHeight int
-		size                    Size
+		size                    imagerequest.Size
 		wantWidth, wantHeight   int
 	}{
-		{"49x8192 at 0x100", 49, 8192, Size{Height: 100}, 1, 167},
-		{"49x49 at 1x1", 49, 49, Size{Width: 1, Height: 1}, 1, 1},
+		{"49x8192 at 0x100", 49, 8192, imagerequest.Size{Height: 100}, 1, 167},
+		{"49x49 at 1x1", 49, 49, imagerequest.Size{Width: 1, Height: 1}, 1, 1},
 	}
 
 	for _, tt := range tests {
@@ -86,7 +97,11 @@ func TestImageProcessor_FitOutsideSideIsAtLeastOne(t *testing.T) {
 
 			result, err := New(Params{}).Process(t.Context(),
 				bytes.NewReader(input),
-				&Request{Size: tt.size, Format: FormatJPEG, FitMode: FitOutside})
+				&imagerequest.Transform{
+					Size:    tt.size,
+					Format:  imagerequest.FormatJPEG,
+					FitMode: imagerequest.FitOutside,
+				})
 			if err != nil {
 				t.Fatalf("Process() error = %v", err)
 			}