From 76934eb094bb5e2e4fa2a0cc69b45707cecf2dc5 Mon Sep 17 00:00:00 2001
From: Poker Design Developer <developer@poker-design.local>
Date: Wed, 3 Jun 2026 22:28:21 +0800
Subject: [PATCH] feat: drawBackSide uses back_design with pattern color tint

---
 frontend/src/utils/cardRenderer.js | 43 +++++++++++++++++++++---------
 1 file changed, 30 insertions(+), 13 deletions(-)

diff --git a/frontend/src/utils/cardRenderer.js b/frontend/src/utils/cardRenderer.js
index 61e146d..ecd611d 100644
--- a/frontend/src/utils/cardRenderer.js
+++ b/frontend/src/utils/cardRenderer.js
@@ -44,6 +44,7 @@ function loadImage(url) {
 async function preloadAll(project) {
   const urls = new Set()
   if (project.design?.background_image) urls.add(project.design.background_image)
+  if (project.back_design?.image) urls.add(project.back_design.image)
   for (const s of Object.keys(project.design?.suit_symbols || {})) {
     const sym = project.design.suit_symbols[s]
     if (sym?.type === 'image' && sym.asset_id) {
@@ -356,19 +357,30 @@ async function drawJokerBody(ctx, w, h, which, design, project) {
   ctx.restore()
 }
 
-async function drawBackSide(ctx, w, h, design, project) {
-  ctx.fillStyle = design.background_color || '#1A237E'
+async function drawBackSide(ctx, w, h, backDesign, project) {
+  ctx.fillStyle = backDesign.background_color || '#1A237E'
   ctx.fillRect(0, 0, w, h)
 
+  const bw = Number(backDesign.border_width) || 0
+  if (bw > 0) {
+    ctx.save()
+    ctx.strokeStyle = backDesign.border_color || '#C0A050'
+    ctx.lineWidth = bw
+    const half = bw / 2
+    drawRoundedRect(ctx, half, half, w - bw, h - bw, 16)
+    ctx.stroke()
+    ctx.restore()
+  }
+
   const padX = Math.round(w * 0.15)
   const padTop = Math.round(h * 0.18)
   const padBot = Math.round(h * 0.22)
   const bodyW = w - 2 * padX
   const bodyH = h - padTop - padBot
 
-  const imageDx = Number(design.image_dx) || 0
-  const imageDy = Number(design.image_dy) || 0
-  const imageScale = Number(design.image_scale) || 1
+  const imageDx = Number(backDesign.image_dx) || 0
+  const imageDy = Number(backDesign.image_dy) || 0
+  const imageScale = Number(backDesign.image_scale) || 1
   const offsetX = bodyW * imageDx
   const offsetY = bodyH * imageDy
 
@@ -393,17 +405,21 @@ async function drawBackSide(ctx, w, h, design, project) {
     const drawX = padX + offsetX + (bodyW - finalW) / 2
     const drawY = padTop + offsetY + (bodyH - finalH) / 2
     ctx.drawImage(img, drawX, drawY, finalW, finalH)
+
+    if (backDesign.pattern_color) {
+      ctx.save()
+      ctx.globalCompositeOperation = 'source-atop'
+      ctx.fillStyle = backDesign.pattern_color
+      ctx.globalAlpha = 0.3
+      ctx.fillRect(0, 0, w, h)
+      ctx.restore()
+    }
   } else {
     ctx.save()
-    ctx.strokeStyle = design.border_color || '#FFFFFF'
-    ctx.lineWidth = 6
-    const m = w * 0.06
-    drawRoundedRect(ctx, m, m, w - 2 * m, h - 2 * m, 16)
-    ctx.stroke()
-    ctx.fillStyle = design.border_color || '#FFFFFF'
+    ctx.fillStyle = backDesign.border_color || '#C0A050'
     ctx.textAlign = 'center'
     ctx.textBaseline = 'middle'
-    ctx.font = `bold ${Math.round(w * 0.1)}px ${design.font_family || 'Times New Roman'}, serif`
+    ctx.font = `bold ${Math.round(w * 0.1)}px Times New Roman, serif`
     ctx.fillText('CARD BACK', w / 2, h / 2)
     ctx.restore()
   }
@@ -444,7 +460,8 @@ export async function renderCard(canvas, project, cardKey) {
     await drawJokerBody(ctx, w, h, which, design, project)
     drawBorder(ctx, w, h, design)
   } else if (cardKey === 'back') {
-    await drawBackSide(ctx, w, h, design, project)
+    const backDesign = getEffectiveBackDesign(project)
+    await drawBackSide(ctx, w, h, backDesign, project)
   } else {
     const [suit, rank] = cardKey.split('-')
     drawBackground(ctx, w, h, design)