---
title: "Quick Start"
author: "Jianhong Ou, Jun Yu, Lihua Julie Zhu"
output: BiocStyle::html_document
date: "`r doc_date()`"
package: "`r pkg_ver('ChIPpeakAnno')`"
vignette: >
  %\VignetteIndexEntry{ChIPpeakAnno Quick Start}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---
```{r, echo=FALSE, results="hide", warning=FALSE}
suppressPackageStartupMessages({
    library(ChIPpeakAnno)
    library(EnsDb.Hsapiens.v75)
    library(TxDb.Hsapiens.UCSC.hg19.knownGene)
    library(org.Hs.eg.db)
})
knitr::opts_chunk$set(warning=FALSE, message=FALSE)
```
# Four steps for peak annotation
The purpose of this quick start is to introduce the four newly implemented functions, `toRanges`, `annoGO`, `annotatePeakInBatch`, and `addGeneIDs` in the new version of the **ChIPpeakAnno**. With those wrapper functions, the annotation of ChIP-Seq peaks becomes streamlined into four major steps:

1 Read peak data with `toGRanges`
2 Generate annotation data with `toGRanges`
3 Annotate peaks with `annotatePeakInBatch`
4 Add additional informations with `addGeneIDs`

Most of time user can use the default settings of the arguments of those functions. This makes the annotation pipeline straightforward and easy to use.

# Use case 1: Four steps to annotate peak data with **EnsDb**
## Step 1: Convert the peak data to `GRanges` with `toGRanges`

```{r quickStart}
## First, load the ChIPpeakAnno package
library(ChIPpeakAnno)
```

```{r import}
path <- system.file("extdata", "Tead4.broadPeak", package="ChIPpeakAnno")
peaks <- toGRanges(path, format="broadPeak")
peaks[1:2]
```
## Step 2: Prepare annotation data with `toGRanges`
```{r annotationData}
library(EnsDb.Hsapiens.v75)
annoData <- toGRanges(EnsDb.Hsapiens.v75)
annoData[1:2]
```
## Step 3: Annotate the peaks with `annotatePeakInBatch`
```{r annotate}
## keep the seqnames in the same style
seqlevelsStyle(peaks) <- seqlevelsStyle(annoData)
## do annotation by nearest TSS
anno <- annotatePeakInBatch(peaks, AnnotationData=annoData)
anno[1:2]
# A pie chart can be used to demonstrate the overlap features of the peaks.
pie1(table(anno$insideFeature))
```
## Step 4: Add additional annotation with `addGeneIDs`
```{r addIDs}
library(org.Hs.eg.db)
anno <- addGeneIDs(anno, orgAnn="org.Hs.eg.db", 
                   feature_id_type="ensembl_gene_id",
                   IDs2Add=c("symbol"))
head(anno)
```
# Use case 2: Annotate the peaks with promoters provided by **TxDb**

This section demonstrates how to annotate the same peak data as in quick start 1 using a new annotation based on **TxDb** with `toGRanges`.

```{r}
library(TxDb.Hsapiens.UCSC.hg19.knownGene)
annoData <- toGRanges(TxDb.Hsapiens.UCSC.hg19.knownGene)
annoData[1:2]
seqlevelsStyle(peaks) <- seqlevelsStyle(annoData)
```
The same `annotatePeakInBatch` function is used to annotate the peaks using annotation data just created. This time we want the peaks within 2kb upstream and up to 300bp downstream of TSS within the gene body.
```{r}
anno <- annotatePeakInBatch(peaks, AnnotationData=annoData, 
                  output="overlapping", 
                  FeatureLocForDistance="TSS",
                  bindingRegion=c(-2000, 300))
anno$symbol <- xget(anno$feature, org.Hs.egSYMBOL)
head(anno)
```
# Use case 3: Annotate the peaks in both sides with nearest transcription start sites within 5K bps.
This section demonstrates the flexibility of the annotaition functions in the ChIPpeakAnno. Instead of building a new annotation data, the argument _bindingTypes_ and _bindingRegion_ in `annoPeak` function  can be set to find the peaks within 5000 bp upstream and downstream of the TSS, which could be the user defined promoter region.

```{r, fig.height=3, fig.width=8}
anno <- annotatePeakInBatch(peaks, AnnotationData=annoData, 
                  output="nearestBiDirectionalPromoters", 
                  bindingRegion=c(-5000, 500))
anno$symbol <- xget(anno$feature, org.Hs.egSYMBOL)
anno[anno$peak=="peak12725"]
```
The annotated peaks can be visualized with R/Bioconductor package **trackViewer** developed by our group.
Following is the sample code to plot the tracks.
```{r trackViewer}
if(require(trackViewer, quietly=TRUE)){
    gr <- peak <- peaks["peak12725"]
    start(gr) <- start(gr) - 5000
    end(gr) <- end(gr) + 5000
    if(.Platform$OS.type != "windows"){
        peak12725 <- importScore(file=system.file("extdata", "Tead4.bigWig", 
                                                  package="ChIPpeakAnno"),
                                 ranges=peak, format = "BigWig")
    }else{## rtracklayer can not import bigWig files on Windows
        load(file.path(dirname(path), "cvglist.rds"))
        peak12725 <- Views(cvglists[["Tead4"]][[as.character(seqnames(peak))]],
                           start(peak),
                           end(peak))
        peak12725 <- viewApply(peak12725, as.numeric)
        tmp <- rep(peak, width(peak))
        width(tmp) <- 1
        tmp <- shift(tmp, shift=0:(width(peak)-1))
        mcols(tmp) <- peak12725
        colnames(mcols(tmp)) <- "score"
        peak12725 <- new("track", dat=tmp, 
                         name="peak12725", 
                         type="data", 
                         format="BED")
    }
    
    trs <- geneModelFromTxdb(TxDb.Hsapiens.UCSC.hg19.knownGene, 
                             org.Hs.eg.db, gr)
    names(trs) <- paste(sapply(trs, function(.ele) .ele@name), names(trs), sep=":")
    optSty <- optimizeStyle(trackList(peak12725, trs, heightDist = c(.3, .7)),
                            theme="bw")
    viewTracks(optSty$tracks, gr=gr, viewerStyle=optSty$style)
}
```