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han4wluc merged 2 commits into from
May 24, 2026
Merged

feat: support inline background transforms #279

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3bafd89
feat: support inline background transforms
han4wluc May 24, 2026
0407648
docs: clarify background transform authoring modes
han4wluc May 24, 2026
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87 changes: 65 additions & 22 deletions docs/RouteEngine.md
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Original file line number Diff line number Diff line change
Expand Up @@ -655,22 +655,22 @@ Built-in effect handling notes:

Actions that can be attached to lines to control presentation:

| Action | Properties | Description |
| ------------ | ---------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------- |
| `screen` | `{ opacity?, blur?, animations? }` | Set whole-screen appearance or transition. `opacity`/`blur` apply to the composed story frame |
| `background` | `{ resourceId?, colorId?, transformId?, opacity?, blur?, animations? }` | Set background/CG. `opacity` maps to renderer alpha; `blur: null` clears background blur |
| `dialogue` | `{ characterId?, character?, character.sprite?, persistCharacter?, content, append?, mode?, ui?, clear? }` | Display dialogue |
| `character` | `{ items }` | Display character sprites. Each item can set transform overrides, `opacity`, and `blur` |
| `visual` | `{ items }` | Display visual elements. Each item can set `layer`, transform overrides, `opacity`, and `blur` |
| `bgm` | `{ resourceId, volume?, loop?, startDelayMs? }` | Play background music |
| `sfx` | `{ items }` | Play sound effects. Each item can include `volume`, `loop`, and `startDelayMs` |
| `voice` | `{ resourceId, volume?, loop?, startDelayMs? }` | Play voice audio from `resources.voices[currentSceneId][resourceId]` |
| `animation` | `{ ... }` | Apply animations |
| `layout` | `{ resourceId }` | Display layout |
| `control` | `{ resourceId }` | Activate control bindings and control UI |
| `choice` | `{ resourceId, items }` | Display choice menu |
| `form` | `{ resourceId, fields, submitActions?, cancelActions? }` | Display a blocking multi-input form |
| `cleanAll` | `true` | Clear all presentation state |
| Action | Properties | Description |
| ------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------- |
| `screen` | `{ opacity?, blur?, animations? }` | Set whole-screen appearance or transition. `opacity`/`blur` apply to the composed story frame |
| `background` | `{ resourceId?, colorId?, transformId?, x?, y?, anchorX?, anchorY?, scaleX?, scaleY?, rotation?, originX?, originY?, opacity?, blur?, animations? }` | Set background/CG. Transform fields are renderer pixels/unitless multipliers/degrees; `blur: null` clears background blur |
| `dialogue` | `{ characterId?, character?, character.sprite?, persistCharacter?, content, append?, mode?, ui?, clear? }` | Display dialogue |
| `character` | `{ items }` | Display character sprites. Each item can set transform overrides, `opacity`, and `blur` |
| `visual` | `{ items }` | Display visual elements. Each item can set `layer`, transform overrides, `opacity`, and `blur` |
| `bgm` | `{ resourceId, volume?, loop?, startDelayMs? }` | Play background music |
| `sfx` | `{ items }` | Play sound effects. Each item can include `volume`, `loop`, and `startDelayMs` |
| `voice` | `{ resourceId, volume?, loop?, startDelayMs? }` | Play voice audio from `resources.voices[currentSceneId][resourceId]` |
| `animation` | `{ ... }` | Apply animations |
| `layout` | `{ resourceId }` | Display layout |
| `control` | `{ resourceId }` | Activate control bindings and control UI |
| `choice` | `{ resourceId, items }` | Display choice menu |
| `form` | `{ resourceId, fields, submitActions?, cancelActions? }` | Display a blocking multi-input form |
| `cleanAll` | `true` | Clear all presentation state |

Animation selections use `animations.resourceId` plus optional
`animations.playback`. `playback.speed` is a unitless multiplier: `1` is normal,
Expand Down Expand Up @@ -715,12 +715,55 @@ callers can use the exported `RENDER_LAYER`, `VISUAL_LAYER`, and
### Item Transform Overrides

`resources.transforms` can define `x`, `y`, `anchorX`, `anchorY`, `scaleX`,
`scaleY`, `rotation`, `originX`, and `originY`. Character and visual items can
override any of those transform fields for a single item. `originX` and
`originY` are passed through to the renderer as the transform origin fields.
New character sprite items still require `transformId`; after an item exists, a
later line can provide only `id` and transform fields to patch that item without
restating its sprites or visual resource.
`scaleY`, `rotation`, `originX`, and `originY`. `x` and `y` use renderer pixels,
anchors are normalized unitless values, scale fields are multipliers, and
`rotation` is degrees. Character and visual items can override any of those
transform fields for a single item. `originX` and `originY` are passed through
to the renderer as the transform origin fields. New character sprite items still
require `transformId`; after an item exists, a later line can provide only `id`
and transform fields to patch that item without restating its sprites or visual
resource.

Background actions can also set `x`, `y`, `anchorX`, `anchorY`, `scaleX`,
`scaleY`, `rotation`, `originX`, and `originY` at the top level. These fields
can override selected values from `transformId`, or position the background
without any `transformId`. Image and video backgrounds default to centered
placement, computed as `x = screen.width / 2` and `y = screen.height / 2`, with
`anchorX: 0.5`, `anchorY: 0.5`, `rotation: 0`, `scaleX: 1`, and `scaleY: 1`.
Layout backgrounds use top-left defaults when a background transform is
authored.

Background transforms support three authoring modes:

| Mode | Behavior |
| --------------------------------- | ---------------------------------------------------------------------- |
| `transformId` only | Use the complete transform resource |
| `transformId` plus inline fields | Start from the transform resource, then override the provided fields |
| inline fields without transformId | Apply the provided fields over the background type's default transform |

```yaml
background:
resourceId: bg_school
transformId: fullscreen

background:
resourceId: bg_school
transformId: fullscreen
scaleX: 1.1
scaleY: 1.1

background:
resourceId: bg_school
x: 960
y: 540
anchorX: 0.5
anchorY: 0.5
rotation: 0
scaleX: 1
scaleY: 1
originX: 960
originY: 540
```

```yaml
character:
Expand Down
2 changes: 1 addition & 1 deletion package.json
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@@ -1,6 +1,6 @@
{
"name": "route-engine-js",
"version": "1.21.0",
"version": "1.22.0",
"description": "A lightweight Visual Novel engine built in JavaScript for creating interactive narrative games with branching storylines",
"repository": {
"type": "git",
Expand Down
20 changes: 19 additions & 1 deletion spec/projectDataSchema.test.js
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Expand Up @@ -191,7 +191,7 @@ describe("projectData schema", () => {
);
});

it("accepts background transformId in presentation actions", () => {
it("accepts background transformId and inline transform fields in presentation actions", () => {
expect(
validatePresentationActions({
background: {
Expand All @@ -202,6 +202,24 @@ describe("projectData schema", () => {
).toBe(true);
expect(validatePresentationActions.errors).toBeNull();

expect(
validatePresentationActions({
background: {
resourceId: "bg1",
x: 100,
y: 120,
anchorX: 0,
anchorY: 1,
scaleX: 1.2,
scaleY: 0.8,
rotation: -8,
originX: 64,
originY: 128,
},
}),
).toBe(true);
expect(validatePresentationActions.errors).toBeNull();

expect(
validatePresentationActions({
character: {
Expand Down
38 changes: 38 additions & 0 deletions spec/system/constructPresentationState.spec.yaml
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Original file line number Diff line number Diff line change
Expand Up @@ -119,6 +119,44 @@ out:
transformId: "centered"
colorId: "backdrop"
---
case: background inline transform update keeps the current background resource
in:
- - background:
resourceId: "mainBackground"
transformId: "centered"
x: 960
y: 540
anchorX: 0.5
anchorY: 0.5
scaleX: 1
scaleY: 1
rotation: 0
originX: 960
originY: 540
- background:
x: 100
y: 120
anchorX: 0
anchorY: 1
scaleX: 1.2
scaleY: 0.8
rotation: -8
originX: 64
originY: 128
out:
background:
resourceId: "mainBackground"
transformId: "centered"
x: 100
y: 120
anchorX: 0
anchorY: 1
scaleX: 1.2
scaleY: 0.8
rotation: -8
originX: 64
originY: 128
---
case: background opacity and blur update keeps the current background resource
in:
- - background:
Expand Down
189 changes: 189 additions & 0 deletions spec/system/renderState/addBackgroundOrCg.spec.yaml
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Expand Up @@ -422,6 +422,129 @@ out:
height: 1080
animations: []
---
case: add background image with inline transform to story container
in:
- elements:
- id: "story"
type: "container"
x: 0
y: 0
children: []
animations: []
- presentationState:
background:
resourceId: "bg1"
x: 100
y: 120
anchorX: 0
anchorY: 1
scaleX: 1.2
scaleY: 0.8
rotation: -8
originX: 64
originY: 128
resources:
images:
bg1:
fileId: "image1.png"
width: 1920
height: 1080
out:
elements:
- id: "story"
type: "container"
x: 0
y: 0
children:
- id: "bg-cg-background-color"
type: "rect"
x: 0
y: 0
width: 1920
height: 1080
fill: "#000000"
- id: "bg-cg-background-sprite"
type: "sprite"
alpha: 1
anchorX: 0
anchorY: 1
rotation: -8
scaleX: 1.2
scaleY: 0.8
originX: 64
originY: 128
x: 100
y: 120
src: "image1.png"
width: 1920
height: 1080
animations: []
---
case: background inline transform overrides transform resource fields
in:
- elements:
- id: "story"
type: "container"
x: 0
y: 0
children: []
animations: []
- presentationState:
background:
resourceId: "bg1"
transformId: "bgTransform"
x: 500
scaleY: 0.75
rotation: 22
originX: 32
originY: 96
resources:
images:
bg1:
fileId: "image1.png"
width: 1920
height: 1080
transforms:
bgTransform:
x: 200
y: 300
anchorX: 0
anchorY: 1
scaleX: 1.25
scaleY: 1
originX: 64
originY: 128
out:
elements:
- id: "story"
type: "container"
x: 0
y: 0
children:
- id: "bg-cg-background-color"
type: "rect"
x: 0
y: 0
width: 1920
height: 1080
fill: "#000000"
- id: "bg-cg-background-sprite"
type: "sprite"
alpha: 1
anchorX: 0
anchorY: 1
rotation: 22
scaleX: 1.25
scaleY: 0.75
originX: 32
originY: 96
x: 500
y: 300
src: "image1.png"
width: 1920
height: 1080
animations: []
---
case: unknown background transformId should throw clear error
in:
- elements:
Expand Down Expand Up @@ -1596,6 +1719,72 @@ out:
fill: "#000000"
animations: []
---
case: add background layout with inline transform
in:
- elements:
- id: "story"
type: "container"
x: 0
y: 0
children: []
animations: []
- presentationState:
background:
resourceId: "bgLayout"
x: 400
y: 250
anchorX: 0
anchorY: 0
rotation: 12
scaleX: 0.75
scaleY: 1.1
originX: 64
originY: 128
resources:
layouts:
bgLayout:
elements:
- id: "bg-panel"
type: "rect"
width: 100
height: 50
colorId: "panel"
colors:
panel:
hex: "#000000"
out:
elements:
- id: "story"
type: "container"
x: 0
y: 0
children:
- id: "bg-cg-background-color"
type: "rect"
x: 0
y: 0
width: 1920
height: 1080
fill: "#000000"
- id: "bg-cg-background-container"
type: "container"
x: 400
y: 250
anchorX: 0
anchorY: 0
rotation: 12
scaleX: 0.75
scaleY: 1.1
originX: 64
originY: 128
children:
- id: "bg-panel"
type: "rect"
width: 100
height: 50
fill: "#000000"
animations: []
---
case: resolves colorId in background layout elements
in:
- elements:
Expand Down
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