Export negative offset bug fixes

public/CHANGELOG.md

@@ -2,6 +2,7 @@ All notable changes to this project will be documented in this file.
 
 ## [1.6.0] - 2025-11-18
 - Improved animation preview modal
+- Add toggle for negative spacing in cells
 
 ## [1.5.0] - 2025-11-17
 - Show offset values in sprite cells and in preview modal

src/App.vue

@@ -135,7 +135,7 @@
 </template>
 
 <script setup lang="ts">
-  import { ref, onMounted } from 'vue';
+  import { ref, onMounted, toRef } from 'vue';
   import FileUploader from './components/FileUploader.vue';
   import SpriteCanvas from './components/SpriteCanvas.vue';
   import Modal from './components/utilities/Modal.vue';
@@ -147,11 +147,13 @@
   import DarkModeToggle from './components/utilities/DarkModeToggle.vue';
   import { useSprites } from './composables/useSprites';
   import { useExport } from './composables/useExport';
+  import { useSettingsStore } from './stores/useSettingsStore';
   import type { SpriteFile } from './types/sprites';
 
+  const settingsStore = useSettingsStore();
   const { sprites, columns, updateSpritePosition, updateSpriteCell, removeSprite, replaceSprite, addSprite, addSpriteWithResize, processImageFiles, alignSprites } = useSprites();
 
-  const { downloadSpritesheet, exportSpritesheetJSON, importSpritesheetJSON, downloadAsGif, downloadAsZip } = useExport(sprites, columns);
+  const { downloadSpritesheet, exportSpritesheetJSON, importSpritesheetJSON, downloadAsGif, downloadAsZip } = useExport(sprites, columns, toRef(settingsStore, 'negativeSpacingEnabled'));
   const isPreviewModalOpen = ref(false);
   const isHelpModalOpen = ref(false);
   const isFeedbackModalOpen = ref(false);

src/components/SpriteCanvas.vue

@@ -18,6 +18,11 @@
           <input id="show-all-sprites" type="checkbox" v-model="showAllSprites" class="mr-2" />
           <label for="show-all-sprites" class="dark:text-gray-200">Compare sprites</label>
         </div>
+        <!-- Negative spacing control -->
+        <div class="flex items-center">
+          <input id="negative-spacing" type="checkbox" v-model="settingsStore.negativeSpacingEnabled" class="mr-2 w-4 h-4" />
+          <label for="negative-spacing" class="dark:text-gray-200 text-sm sm:text-base">Negative spacing</label>
+        </div>
       </div>
     </div>
 
@@ -157,6 +162,7 @@
     columns: toRef(props, 'columns'),
     zoom,
     allowCellSwap,
+    negativeSpacingEnabled: toRef(settingsStore, 'negativeSpacingEnabled'),
     getMousePosition: (event, z) => canvas2D.getMousePosition(event, z),
     onUpdateSprite: (id, x, y) => emit('updateSprite', id, x, y),
     onUpdateSpriteCell: (id, newIndex) => emit('updateSpriteCell', id, newIndex),
@@ -271,7 +277,7 @@
   function drawCanvas() {
     if (!canvasRef.value || !canvas2D.ctx.value) return;
 
-    const { maxWidth, maxHeight } = calculateMaxDimensions();
+    const { maxWidth, maxHeight, negativeSpacing } = calculateMaxDimensions();
 
     // Set canvas size
     const rows = Math.max(1, Math.ceil(props.sprites.length / props.columns));
@@ -308,9 +314,10 @@
         const cellY = Math.floor(cellRow * maxHeight);
 
         // Draw all sprites with transparency in this cell
+        // Position at bottom-right with negative spacing offset
         props.sprites.forEach((sprite, spriteIndex) => {
           if (spriteIndex !== cellIndex) {
-            canvas2D.drawImage(sprite.img, cellX + sprite.x, cellY + sprite.y, 0.3);
+            canvas2D.drawImage(sprite.img, cellX + negativeSpacing + sprite.x, cellY + negativeSpacing + sprite.y, 0.3);
           }
         });
       }
@@ -329,8 +336,8 @@
       const cellX = Math.floor(col * maxWidth);
       const cellY = Math.floor(row * maxHeight);
 
-      // Draw sprite
-      canvas2D.drawImage(sprite.img, cellX + sprite.x, cellY + sprite.y);
+      // Draw sprite with negative spacing offset (bottom-right positioning)
+      canvas2D.drawImage(sprite.img, cellX + negativeSpacing + sprite.x, cellY + negativeSpacing + sprite.y);
     });
 
     // Draw ghost sprite if we're dragging between cells
@@ -395,6 +402,7 @@
   watch(() => props.columns, drawCanvas);
   watch(() => settingsStore.pixelPerfect, drawCanvas);
   watch(() => settingsStore.darkMode, drawCanvas);
+  watch(() => settingsStore.negativeSpacingEnabled, drawCanvas);
   watch(showAllSprites, drawCanvas);
 </script>
 

src/components/SpritePreview.vue

@@ -209,6 +209,18 @@
 
   // Canvas drawing
 
+  // Calculate negative spacing based on sprite dimensions
+  function calculateNegativeSpacing(): number {
+    if (!settingsStore.negativeSpacingEnabled || props.sprites.length === 0) return 0;
+
+    const { maxWidth, maxHeight } = getMaxDimensions(props.sprites);
+    const minWidth = Math.min(...props.sprites.map(s => s.width));
+    const minHeight = Math.min(...props.sprites.map(s => s.height));
+    const widthDiff = maxWidth - minWidth;
+    const heightDiff = maxHeight - minHeight;
+    return Math.max(widthDiff, heightDiff);
+  }
+
   function drawPreviewCanvas() {
     if (!previewCanvasRef.value || !canvas2D.ctx.value || props.sprites.length === 0) return;
 
@@ -216,33 +228,36 @@
     if (!currentSprite) return;
 
     const { maxWidth, maxHeight } = getMaxDimensions(props.sprites);
+    const negativeSpacing = calculateNegativeSpacing();
+    const cellWidth = maxWidth + negativeSpacing;
+    const cellHeight = maxHeight + negativeSpacing;
 
     // Apply pixel art optimization
     canvas2D.applySmoothing();
 
-    // Set canvas size to just fit one sprite cell
-    canvas2D.setCanvasSize(maxWidth, maxHeight);
+    // Set canvas size to fit one sprite cell (expanded with negative spacing)
+    canvas2D.setCanvasSize(cellWidth, cellHeight);
 
     // Clear canvas
     canvas2D.clear();
 
     // Draw grid background (cell)
-    canvas2D.fillRect(0, 0, maxWidth, maxHeight, '#f9fafb');
+    canvas2D.fillRect(0, 0, cellWidth, cellHeight, '#f9fafb');
 
     // Draw all sprites with transparency if enabled
     if (showAllSprites.value && props.sprites.length > 1) {
       props.sprites.forEach((sprite, index) => {
         if (index !== currentFrameIndex.value && !hiddenFrames.value.includes(index)) {
-          canvas2D.drawImage(sprite.img, sprite.x, sprite.y, 0.3);
+          canvas2D.drawImage(sprite.img, negativeSpacing + sprite.x, negativeSpacing + sprite.y, 0.3);
         }
       });
     }
 
-    // Draw current sprite
-    canvas2D.drawImage(currentSprite.img, currentSprite.x, currentSprite.y);
+    // Draw current sprite with negative spacing offset
+    canvas2D.drawImage(currentSprite.img, negativeSpacing + currentSprite.x, negativeSpacing + currentSprite.y);
 
     // Draw cell border
-    canvas2D.strokeRect(0, 0, maxWidth, maxHeight, '#e5e7eb', 1);
+    canvas2D.strokeRect(0, 0, cellWidth, cellHeight, '#e5e7eb', 1);
   }
 
   // Drag functionality
@@ -257,9 +272,12 @@
     const mouseY = ((event.clientY - rect.top) / zoom.value) * scaleY;
 
     const sprite = props.sprites[currentFrameIndex.value];
+    const negativeSpacing = calculateNegativeSpacing();
 
-    // Check if click is on sprite
-    if (sprite && mouseX >= sprite.x && mouseX <= sprite.x + sprite.width && mouseY >= sprite.y && mouseY <= sprite.y + sprite.height) {
+    // Check if click is on sprite (accounting for negative spacing offset)
+    const spriteCanvasX = negativeSpacing + sprite.x;
+    const spriteCanvasY = negativeSpacing + sprite.y;
+    if (sprite && mouseX >= spriteCanvasX && mouseX <= spriteCanvasX + sprite.width && mouseY >= spriteCanvasY && mouseY <= spriteCanvasY + sprite.height) {
       isDragging.value = true;
       activeSpriteId.value = sprite.id;
       dragStartX.value = mouseX;
@@ -285,14 +303,17 @@
     if (!sprite || sprite.id !== activeSpriteId.value) return;
 
     const { maxWidth, maxHeight } = getMaxDimensions(props.sprites);
+    const negativeSpacing = calculateNegativeSpacing();
+    const cellWidth = maxWidth + negativeSpacing;
+    const cellHeight = maxHeight + negativeSpacing;
 
     // Calculate new position with constraints and round to integers
     let newX = Math.round(spritePosBeforeDrag.value.x + deltaX);
     let newY = Math.round(spritePosBeforeDrag.value.y + deltaY);
 
-    // Constrain movement within cell
-    newX = Math.max(0, Math.min(maxWidth - sprite.width, newX));
-    newY = Math.max(0, Math.min(maxHeight - sprite.height, newY));
+    // Constrain movement within expanded cell (allow negative values up to -negativeSpacing)
+    newX = Math.max(-negativeSpacing, Math.min(cellWidth - negativeSpacing - sprite.width, newX));
+    newY = Math.max(-negativeSpacing, Math.min(cellHeight - negativeSpacing - sprite.height, newY));
 
     emit('updateSprite', activeSpriteId.value, newX, newY);
     drawPreviewCanvas();
@@ -362,6 +383,7 @@
   watch(showAllSprites, drawPreviewCanvas);
   watch(hiddenFrames, drawPreviewCanvas);
   watch(() => settingsStore.pixelPerfect, drawPreviewCanvas);
+  watch(() => settingsStore.negativeSpacingEnabled, drawPreviewCanvas);
 
   // Initial draw
   if (props.sprites.length > 0) {

src/composables/useDragSprite.ts

@@ -30,6 +30,7 @@ export interface DragSpriteOptions {
   columns: Ref<number> | number;
   zoom?: Ref<number>;
   allowCellSwap?: Ref<boolean>;
+  negativeSpacingEnabled?: Ref<boolean>;
   getMousePosition: (event: MouseEvent, zoom?: number) => { x: number; y: number } | null;
   onUpdateSprite: (id: string, x: number, y: number) => void;
   onUpdateSpriteCell?: (id: string, newIndex: number) => void;
@@ -44,6 +45,7 @@ export function useDragSprite(options: DragSpriteOptions) {
   const getColumns = () => (typeof options.columns === 'number' ? options.columns : options.columns.value);
   const getZoom = () => options.zoom?.value ?? 1;
   const getAllowCellSwap = () => options.allowCellSwap?.value ?? false;
+  const getNegativeSpacingEnabled = () => options.negativeSpacingEnabled?.value ?? false;
 
   // Drag state
   const isDragging = ref(false);
@@ -65,28 +67,47 @@ export function useDragSprite(options: DragSpriteOptions) {
 
   const calculateMaxDimensions = () => {
     const sprites = getSprites();
+    const negativeSpacingEnabled = getNegativeSpacingEnabled();
     const base = getMaxDimensions(sprites);
-    const maxWidth = Math.max(1, base.maxWidth, lastMaxWidth.value);
-    const maxHeight = Math.max(1, base.maxHeight, lastMaxHeight.value);
-    lastMaxWidth.value = maxWidth;
-    lastMaxHeight.value = maxHeight;
-    return { maxWidth, maxHeight };
+    const baseMaxWidth = Math.max(1, base.maxWidth, lastMaxWidth.value);
+    const baseMaxHeight = Math.max(1, base.maxHeight, lastMaxHeight.value);
+    lastMaxWidth.value = baseMaxWidth;
+    lastMaxHeight.value = baseMaxHeight;
+
+    // Calculate negative spacing based on sprite size differences
+    let negativeSpacing = 0;
+    if (negativeSpacingEnabled && sprites.length > 0) {
+      // Find the smallest sprite dimensions
+      const minWidth = Math.min(...sprites.map(s => s.width));
+      const minHeight = Math.min(...sprites.map(s => s.height));
+      // Negative spacing is the difference between max and min dimensions
+      const widthDiff = baseMaxWidth - minWidth;
+      const heightDiff = baseMaxHeight - minHeight;
+      negativeSpacing = Math.max(widthDiff, heightDiff);
+    }
+
+    // Add negative spacing to expand each cell
+    const maxWidth = baseMaxWidth + negativeSpacing;
+    const maxHeight = baseMaxHeight + negativeSpacing;
+    return { maxWidth, maxHeight, negativeSpacing };
   };
 
   // Computed sprite positions
   const spritePositions = computed<SpritePosition[]>(() => {
     const sprites = getSprites();
     const columns = getColumns();
-    const { maxWidth, maxHeight } = calculateMaxDimensions();
+    const { maxWidth, maxHeight, negativeSpacing } = calculateMaxDimensions();
 
     return sprites.map((sprite, index) => {
       const col = index % columns;
       const row = Math.floor(index / columns);
 
+      // With negative spacing, sprites are positioned at bottom-right of cell
+      // (spacing added to top and left)
       return {
         id: sprite.id,
-        canvasX: col * maxWidth + sprite.x,
-        canvasY: row * maxHeight + sprite.y,
+        canvasX: col * maxWidth + negativeSpacing + sprite.x,
+        canvasY: row * maxHeight + negativeSpacing + sprite.y,
         cellX: col * maxWidth,
         cellY: row * maxHeight,
         width: sprite.width,
@@ -162,7 +183,7 @@ export function useDragSprite(options: DragSpriteOptions) {
     if (!activeSpriteId.value) return;
     const sprites = getSprites();
     const columns = getColumns();
-    const { maxWidth, maxHeight } = calculateMaxDimensions();
+    const { maxWidth, maxHeight, negativeSpacing } = calculateMaxDimensions();
 
     // Use the sprite's current index in the array to calculate cell position
     const cellCol = spriteIndex % columns;
@@ -170,11 +191,15 @@ export function useDragSprite(options: DragSpriteOptions) {
     const cellX = cellCol * maxWidth;
     const cellY = cellRow * maxHeight;
 
-    const newX = mouseX - cellX - dragOffsetX.value;
-    const newY = mouseY - cellY - dragOffsetY.value;
+    // Calculate new position relative to cell origin (without the negative spacing offset)
+    // The sprite's x,y is stored relative to where it would be drawn after the negativeSpacing offset
+    const newX = mouseX - cellX - negativeSpacing - dragOffsetX.value;
+    const newY = mouseY - cellY - negativeSpacing - dragOffsetY.value;
 
-    const constrainedX = Math.floor(Math.max(0, Math.min(maxWidth - sprites[spriteIndex].width, newX)));
-    const constrainedY = Math.floor(Math.max(0, Math.min(maxHeight - sprites[spriteIndex].height, newY)));
+    // The sprite can move within the full expanded cell area
+    // Allow negative values up to -negativeSpacing so sprite can fill the expanded area
+    const constrainedX = Math.floor(Math.max(-negativeSpacing, Math.min(maxWidth - negativeSpacing - sprites[spriteIndex].width, newX)));
+    const constrainedY = Math.floor(Math.max(-negativeSpacing, Math.min(maxHeight - negativeSpacing - sprites[spriteIndex].height, newY)));
 
     onUpdateSprite(activeSpriteId.value, constrainedX, constrainedY);
     onDraw();

src/composables/useExport.ts

@@ -5,7 +5,18 @@ import JSZip from 'jszip';
 import type { Sprite } from '../types/sprites';
 import { getMaxDimensions } from './useSprites';
 
-export const useExport = (sprites: Ref<Sprite[]>, columns: Ref<number>) => {
+export const useExport = (sprites: Ref<Sprite[]>, columns: Ref<number>, negativeSpacingEnabled: Ref<boolean>) => {
+  // Calculate negative spacing based on sprite dimensions
+  const calculateNegativeSpacing = (): number => {
+    if (!negativeSpacingEnabled.value || sprites.value.length === 0) return 0;
+
+    const { maxWidth, maxHeight } = getMaxDimensions(sprites.value);
+    const minWidth = Math.min(...sprites.value.map(s => s.width));
+    const minHeight = Math.min(...sprites.value.map(s => s.height));
+    const widthDiff = maxWidth - minWidth;
+    const heightDiff = maxHeight - minHeight;
+    return Math.max(widthDiff, heightDiff);
+  };
   const downloadSpritesheet = () => {
     if (!sprites.value.length) {
       alert('Please upload or import sprites before downloading the spritesheet.');
@@ -13,22 +24,25 @@ export const useExport = (sprites: Ref<Sprite[]>, columns: Ref<number>) => {
     }
 
     const { maxWidth, maxHeight } = getMaxDimensions(sprites.value);
+    const negativeSpacing = calculateNegativeSpacing();
+    const cellWidth = maxWidth + negativeSpacing;
+    const cellHeight = maxHeight + negativeSpacing;
     const rows = Math.ceil(sprites.value.length / columns.value);
 
     const canvas = document.createElement('canvas');
     const ctx = canvas.getContext('2d');
     if (!ctx) return;
 
-    canvas.width = maxWidth * columns.value;
-    canvas.height = maxHeight * rows;
+    canvas.width = cellWidth * columns.value;
+    canvas.height = cellHeight * rows;
     ctx.imageSmoothingEnabled = false;
 
     sprites.value.forEach((sprite, index) => {
       const col = index % columns.value;
       const row = Math.floor(index / columns.value);
-      const cellX = Math.floor(col * maxWidth);
-      const cellY = Math.floor(row * maxHeight);
-      ctx.drawImage(sprite.img, Math.floor(cellX + sprite.x), Math.floor(cellY + sprite.y));
+      const cellX = Math.floor(col * cellWidth);
+      const cellY = Math.floor(row * cellHeight);
+      ctx.drawImage(sprite.img, Math.floor(cellX + negativeSpacing + sprite.x), Math.floor(cellY + negativeSpacing + sprite.y));
     });
 
     const link = document.createElement('a');
@@ -133,20 +147,23 @@ export const useExport = (sprites: Ref<Sprite[]>, columns: Ref<number>) => {
     }
 
     const { maxWidth, maxHeight } = getMaxDimensions(sprites.value);
+    const negativeSpacing = calculateNegativeSpacing();
+    const cellWidth = maxWidth + negativeSpacing;
+    const cellHeight = maxHeight + negativeSpacing;
     const canvas = document.createElement('canvas');
     const ctx = canvas.getContext('2d');
     if (!ctx) return;
-    canvas.width = maxWidth;
-    canvas.height = maxHeight;
+    canvas.width = cellWidth;
+    canvas.height = cellHeight;
     ctx.imageSmoothingEnabled = false;
 
-    const gif = new GIF({ workers: 2, quality: 10, width: maxWidth, height: maxHeight, workerScript: gifWorkerUrl });
+    const gif = new GIF({ workers: 2, quality: 10, width: cellWidth, height: cellHeight, workerScript: gifWorkerUrl });
 
     sprites.value.forEach(sprite => {
       ctx.clearRect(0, 0, canvas.width, canvas.height);
       ctx.fillStyle = '#f9fafb';
-      ctx.fillRect(0, 0, maxWidth, maxHeight);
-      ctx.drawImage(sprite.img, Math.floor(sprite.x), Math.floor(sprite.y));
+      ctx.fillRect(0, 0, cellWidth, cellHeight);
+      ctx.drawImage(sprite.img, Math.floor(negativeSpacing + sprite.x), Math.floor(negativeSpacing + sprite.y));
       gif.addFrame(ctx, { copy: true, delay: 1000 / fps });
     });
 
@@ -170,18 +187,21 @@ export const useExport = (sprites: Ref<Sprite[]>, columns: Ref<number>) => {
 
     const zip = new JSZip();
     const { maxWidth, maxHeight } = getMaxDimensions(sprites.value);
+    const negativeSpacing = calculateNegativeSpacing();
+    const cellWidth = maxWidth + negativeSpacing;
+    const cellHeight = maxHeight + negativeSpacing;
     const canvas = document.createElement('canvas');
     const ctx = canvas.getContext('2d');
     if (!ctx) return;
-    canvas.width = maxWidth;
-    canvas.height = maxHeight;
+    canvas.width = cellWidth;
+    canvas.height = cellHeight;
     ctx.imageSmoothingEnabled = false;
 
     sprites.value.forEach((sprite, index) => {
       ctx.clearRect(0, 0, canvas.width, canvas.height);
       ctx.fillStyle = '#f9fafb';
-      ctx.fillRect(0, 0, maxWidth, maxHeight);
-      ctx.drawImage(sprite.img, Math.floor(sprite.x), Math.floor(sprite.y));
+      ctx.fillRect(0, 0, cellWidth, cellHeight);
+      ctx.drawImage(sprite.img, Math.floor(negativeSpacing + sprite.x), Math.floor(negativeSpacing + sprite.y));
       const dataURL = canvas.toDataURL('image/png');
       const binary = atob(dataURL.split(',')[1]);
       const buf = new ArrayBuffer(binary.length);

src/stores/useSettingsStore.ts

@@ -3,6 +3,7 @@ import { ref, watch } from 'vue';
 
 const pixelPerfect = ref(true);
 const darkMode = ref(false);
+const negativeSpacingEnabled = ref(false);
 
 // Initialize dark mode from localStorage or system preference
 if (typeof window !== 'undefined') {
@@ -51,12 +52,18 @@ export const useSettingsStore = defineStore('settings', () => {
     darkMode.value = value;
   }
 
+  function toggleNegativeSpacing() {
+    negativeSpacingEnabled.value = !negativeSpacingEnabled.value;
+  }
+
   return {
     pixelPerfect,
     darkMode,
+    negativeSpacingEnabled,
     togglePixelPerfect,
     setPixelPerfect,
     toggleDarkMode,
     setDarkMode,
+    toggleNegativeSpacing,
   };
 });