Add common layout components for PDF

feature/pdf/src/commonMain/kotlin/org/groundplatform/feature/pdf/render/PdfConfig.kt

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+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.groundplatform.feature.pdf.render
+
+/**
+ * Dimensional and type-scale constants shared by the Android and iOS PDF renderers. Keeping these
+ * in commonMain prevents the two platforms from drifting on page size, margins, or type scale.
+ *
+ * Unless noted otherwise, all measurements are in PDF points (1/72 inch).
+ */
+internal object PdfConfig {
+  /** Page width in points (A4 portrait, 210mm). */
+  const val PAGE_WIDTH = 595
+
+  /** Page height in points (A4 portrait, 297mm). */
+  const val PAGE_HEIGHT = 842
+
+  /** Page margin applied to all four edges. */
+  const val MARGIN = 40
+
+  /** Font size for title text. */
+  const val TITLE_SIZE = 11f
+
+  /** Font size body and table-cell text. */
+  const val BODY_SIZE = 11f
+
+  /** Font size for captions and metadata (header/footer) text. */
+  const val CAPTION_SIZE = 9f
+
+  /** Vertical spacing added between lines of text. */
+  const val LINE_SPACING = 4f
+
+  /** Content width between the left and right margins. */
+  const val USABLE_WIDTH = PAGE_WIDTH - 2 * MARGIN
+
+  /** Resolution in dots-per-inch used when rasterizing images for the PDF. */
+  const val IMAGE_RENDER_DPI = 300f
+}

feature/pdf/src/commonMain/kotlin/org/groundplatform/feature/pdf/render/PdfGeometry.kt

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+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.groundplatform.feature.pdf.render
+
+import kotlin.math.roundToInt
+
+internal fun fitInside(width: Int, height: Int, maxWidth: Int, maxHeight: Int): PdfItemSize {
+  val scale = minOf(maxWidth.toFloat() / width, maxHeight.toFloat() / height, 1f)
+  return PdfItemSize(width * scale, height * scale)
+}
+
+internal fun pointsToRenderPixels(points: Float): Int =
+  // 1 point = 1/72 inch (standard PDF user-space unit)
+  (points / 72f * PdfConfig.IMAGE_RENDER_DPI).roundToInt()
+
+internal data class PdfItemSize(val width: Float, val height: Float)
+
+internal data class PdfOffset(val x: Float, val y: Float)
+
+internal data class PdfLine(val startX: Float, val startY: Float, val endX: Float, val endY: Float)
+
+/** Platform-agnostic rectangle defined by its top-left corner and dimensions. */
+internal data class PdfRect(val x: Float, val y: Float, val width: Float, val height: Float) {
+  val right: Float
+    get() = x + width
+
+  val bottom: Float
+    get() = y + height
+}

feature/pdf/src/commonMain/kotlin/org/groundplatform/feature/pdf/render/layout/PageFooterLayout.kt

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+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.groundplatform.feature.pdf.render.layout
+
+import org.groundplatform.feature.pdf.render.PdfConfig.MARGIN
+import org.groundplatform.feature.pdf.render.PdfConfig.PAGE_HEIGHT
+import org.groundplatform.feature.pdf.render.PdfConfig.USABLE_WIDTH
+import org.groundplatform.feature.pdf.render.PdfOffset
+
+/**
+ * Pre-computed layout for the page footer with separate left and right slots.
+ *
+ * @param footerTextOffset The top-left position where the footer text begins.
+ * @param pageNumberOffset The top-left position where the page number begins.
+ * @param pageNumberMaxWidth The maximum width available for the page number
+ */
+internal data class PageFooterLayout(
+  val footerTextOffset: PdfOffset,
+  val pageNumberOffset: PdfOffset,
+  val pageNumberMaxWidth: Int,
+) {
+  companion object {
+    /** Vertical gap above the footer separating it from body content. */
+    const val TOP_GAP = 28f
+
+    /** Width reserved on the footer's right side for the page-number label. */
+    const val PAGE_NUMBER_BAND_WIDTH = 60
+
+    /** Minimum horizontal gap between the footer text and the page number. */
+    const val PAGE_NUMBER_GAP = 8
+
+    /** Maximum width for footer text (usable width minus the page-number band and its gap). */
+    const val TEXT_MAX_WIDTH = USABLE_WIDTH - PAGE_NUMBER_BAND_WIDTH - PAGE_NUMBER_GAP
+
+    /** Maximum number of lines rendered for the footer text. */
+    const val MAX_LINES = 1
+
+    /**
+     * Vertical space the footer occupies, including the [TOP_GAP] separating it from page content.
+     */
+    fun reserve(footerHeight: Float): Float = footerHeight + TOP_GAP
+
+    fun compute(footerHeight: Float): PageFooterLayout {
+      val top = PAGE_HEIGHT - MARGIN - footerHeight
+      val left = MARGIN.toFloat()
+      val pageNumberLeft = left + USABLE_WIDTH - PAGE_NUMBER_BAND_WIDTH
+      return PageFooterLayout(
+        footerTextOffset = PdfOffset(left, top),
+        pageNumberOffset = PdfOffset(pageNumberLeft, top),
+        pageNumberMaxWidth = PAGE_NUMBER_BAND_WIDTH,
+      )
+    }
+  }
+}

feature/pdf/src/commonMain/kotlin/org/groundplatform/feature/pdf/render/layout/PageHeaderLayout.kt

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+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.groundplatform.feature.pdf.render.layout
+
+import org.groundplatform.feature.pdf.render.PdfConfig.LINE_SPACING
+import org.groundplatform.feature.pdf.render.PdfConfig.MARGIN
+import org.groundplatform.feature.pdf.render.PdfConfig.USABLE_WIDTH
+import org.groundplatform.feature.pdf.render.PdfOffset
+
+/**
+ * Pre-computed layout for the page header with three slots. Assumes uniform typography across
+ * columns.
+ *
+ * @param leftColumn Label and value positions for the left column.
+ * @param centerColumn Label and value positions for the center column.
+ * @param rightTextOffset The position where the right-aligned value begins .
+ * @param nextCursorY The Y position where the cursor should be positioned after the header.
+ */
+internal data class PageHeaderLayout(
+  val leftColumn: Column,
+  val centerColumn: Column,
+  val rightTextOffset: PdfOffset,
+  val nextCursorY: Float,
+) {
+  companion object {
+    /** Horizontal gap between the two columns of the page header. */
+    const val COLUMN_GAP = 16
+    /** Vertical gap below the header before body content begins. */
+    const val BOTTOM_GAP = 28f
+
+    /** Maximum number of lines rendered for each header value. */
+    const val MAX_LINES = 1
+    const val COLUMN_WIDTH: Int = (USABLE_WIDTH - 2 * COLUMN_GAP) / 3
+    const val LEFT_X: Float = MARGIN.toFloat()
+    const val CENTER_X: Float = LEFT_X + COLUMN_WIDTH + COLUMN_GAP
+    const val RIGHT_X: Float = LEFT_X + 2 * (COLUMN_WIDTH + COLUMN_GAP)
+
+    fun compute(top: Float, labelHeight: Float, valueHeight: Float): PageHeaderLayout {
+      val columnBottom = top + labelHeight + LINE_SPACING + valueHeight
+      return PageHeaderLayout(
+        leftColumn = column(LEFT_X, top, labelHeight),
+        centerColumn = column(CENTER_X, top, labelHeight),
+        rightTextOffset = PdfOffset(RIGHT_X, top),
+        nextCursorY = columnBottom + BOTTOM_GAP,
+      )
+    }
+
+    private fun column(x: Float, top: Float, labelHeight: Float) =
+      Column(
+        labelOffset = PdfOffset(x, top),
+        valueOffset = PdfOffset(x, top + labelHeight + LINE_SPACING),
+      )
+  }
+
+  data class Column(val labelOffset: PdfOffset, val valueOffset: PdfOffset)
+}

feature/pdf/src/commonMain/kotlin/org/groundplatform/feature/pdf/render/layout/QrBlockLayout.kt

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+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.groundplatform.feature.pdf.render.layout
+
+import org.groundplatform.feature.pdf.render.PdfConfig.LINE_SPACING
+import org.groundplatform.feature.pdf.render.PdfConfig.MARGIN
+import org.groundplatform.feature.pdf.render.PdfConfig.PAGE_WIDTH
+import org.groundplatform.feature.pdf.render.PdfOffset
+import org.groundplatform.feature.pdf.render.PdfRect
+
+/**
+ * Pre-computed layout for the right-aligned QR code block with its caption. Compute should only be
+ * called when a QR image is available; the caption is meaningless without it.
+ *
+ * @param qrFrame Position and size of the QR image.
+ * @param captionOffset Top-left position of the caption text (centered under the QR).
+ * @param nextCursorY Cursor Y position after this block.
+ */
+internal data class QrBlockLayout(
+  val qrFrame: PdfRect,
+  val captionOffset: PdfOffset,
+  val nextCursorY: Float,
+) {
+  companion object {
+    /** Target size of the QR code block. */
+    const val QR_SIZE = 200f
+
+    fun compute(top: Float, captionHeight: Float): QrBlockLayout {
+      val x = PAGE_WIDTH - MARGIN - QR_SIZE
+      val captionTop = top + QR_SIZE + LINE_SPACING
+      return QrBlockLayout(
+        qrFrame = PdfRect(x, top, QR_SIZE, QR_SIZE),
+        captionOffset = PdfOffset(x, captionTop),
+        nextCursorY = captionTop + captionHeight + LINE_SPACING * 2,
+      )
+    }
+  }
+}