Size Flash streams to the exact SWF stage

Scaling the display up relied on full screen scaling the movie, but games
that set StageScaleMode.NO_SCALE stay at their native size in full screen,
leaving a small game against black. At the exact stage size, full screen
fits every scale mode and the browser scales the stream.

streaming/README.md

@@ -53,7 +53,7 @@ in secure contexts.
 A game is streamable when its platform is in `STREAM_PLATFORMS` (default
 `Java,Shockwave,Flash`) and the streamer can resolve its launcher. The display
 is sized from the content it launches: a Director movie's or projector's stage,
-a SWF's stage scaled up to fit 1280x960, a page's applet or largest embed, with
+a SWF's stage, a page's applet or largest embed, with
 fallbacks of 800x600, or 1024x768 for pages.
 
 Saves are `{relative path: base64 contents}` for the files under the

streaming/session-manager/src/games.ts

@@ -11,9 +11,6 @@ const JAVA_APPS = new Set(['fpsoftware\\startjava.bat', 'fpsoftware\\startjavain
 const DEFAULT_SIZE: Size = { width: 800, height: 600 };
 const BROWSER_SIZE: Size = { width: 1024, height: 768 };
 
-/** Flash is vector art, so it renders sharper at a larger display than its stage. */
-const FLASH_MAX: Size = { width: 1280, height: 960 };
-
 /** A page's default body margin around embedded content. */
 const PAGE_MARGIN = 8;
 
@@ -79,7 +76,8 @@ export class GameCatalog {
       return even((content && directorStageSize(content)) ?? DEFAULT_SIZE);
     }
     if (extension === '.swf') {
-      return even(scaleToFit((content && swfStageSize(content)) ?? DEFAULT_SIZE, FLASH_MAX));
+      // The exact stage: in full screen, games that set noScale keep their native size
+      return even((content && swfStageSize(content)) ?? DEFAULT_SIZE);
     }
     const embed = content && embedSize(content.toString('latin1'));
     return even(embed ? { width: embed.width + 2 * PAGE_MARGIN, height: embed.height + 2 * PAGE_MARGIN } : BROWSER_SIZE);
@@ -158,11 +156,6 @@ function even({ width, height }: Size): Size {
   return { width: width + (width % 2), height: height + (height % 2) };
 }
 
-function scaleToFit(size: Size, max: Size): Size {
-  const scale = Math.min(max.width / size.width, max.height / size.height);
-  return scale > 1 ? { width: Math.round(size.width * scale), height: Math.round(size.height * scale) } : size;
-}
-
 /** Reads the stage size from a SWF header: a rect of twips after the 8-byte header. */
 export function swfStageSize(swf: Buffer): Size | null {
   const signature = swf.toString('latin1', 0, 3);

streaming/session-manager/test/games.test.ts

@@ -181,7 +181,7 @@ test('GameCatalog streams allowed platforms whose launcher resolves, sized from
     oldcpu: { width: 500, height: 426 },
     secure: { width: 640, height: 480 },
     navigator: { width: 528, height: 400 },
-    flash: { width: 1280, height: 960 },
+    flash: { width: 500, height: 376 },
     unity: null,
     'no-program': null,
     exe: { width: 800, height: 600 },